James Smallcombe: And that brings us to the end of the introductions and so I shall now hand over to getting and so please tell us about your work.
Kathrin Wimmer: Okay, thank you very much.
Kathrin Wimmer: I hope you can all hear me.
Kathrin Wimmer: So, first of all I would like to think say thank you to James and the organizers of the seminar for this invitation.
Kathrin Wimmer: And I also apologize, I was scheduled to talk in November last year, but then the experimental campaign that we have been running here got delayed and I unfortunately had to cancel so i'm very happy that I still have the opportunity now to present our recent finished work.
Kathrin Wimmer: On shape changes in mirror nuclei.
Kathrin Wimmer: So in this talk, I will start with the usual introduction and motivation for all work and then I will present the experimental technique of in being gamma Ray spectroscopy at Dr BF in Japan.
Kathrin Wimmer: And then I will discuss the two main results of this campaign so first we studied krypton 72 and I will discuss shape coexistence there and second topic is the title of the talk shape changes of miro nuclei selenium 70 and krypton 70 and I will finish with summary and outlook.
Kathrin Wimmer: So a very fundamental concept of nuclear physics is ISIS been symmetry we can regard the proton and neutron as to representations of rookie on.
Kathrin Wimmer: With ISIS spin quantum number plus or minus one half and this very fundamental concept lead also to with the concept and of the quarks as the constituents of the Nokia.
Kathrin Wimmer: So, if we look to Nokia on system.
Kathrin Wimmer: of either to protons or to neutrons or proton and neutron we can categorize them as the T equals one triplet and T equals zero singlet state.
Kathrin Wimmer: And this concept also easily explained you already the spinning parity of the neutron as one plus.
Kathrin Wimmer: And the strong interaction is independent of ISIS spin or the charge that means that the proton neutron to action is the average of the program proton and the neutral neutral injection.
Kathrin Wimmer: The interaction is also symmetric under the exchange of protons and neutrons so the proton proton into action is identical to the neutral neutral intact.
Kathrin Wimmer: So, assuming that we have this I suspend symmetry the year spectrum of mirror nuclei are identical, and he has shown the example of mass 22.
Kathrin Wimmer: triplet with magnesium 22 was full of protons and neutrons and neon 22 with 10 protons and neutrons and the ot ot nucleus was 11 protons and neutrons.
Kathrin Wimmer: And you can see here and read the excitation energy spectra of these T equal one states, and they are almost identical.
Kathrin Wimmer: Obviously the column, and the action of the protons leads to small differences in these excitation energies, but this can be calculated precisely.
Kathrin Wimmer: So, by looking at the energy difference and the excitation energy Of these, I suspend triplets we can test the ISIS spin dependence or independence of the nuclear attack.
Kathrin Wimmer: If you look at these triplet states we consider a proton which nucleus with tz equals minus one and it's Mariano close the neutron rich nucleus stc equals plus one, and then we have the N equals G ot ot nucleus was T zero.
Kathrin Wimmer: There are several quantities that we can probe the first thing is the mirror energy difference, so this is the energy difference between the proton which the excitation energy in the problem which system and the neutral nutrisystem.
Kathrin Wimmer: And this tests, the charge Secretary of the nuclear into action, so if the proton proton and neutron alternate action are identical.
Kathrin Wimmer: Then we can also look at triplet energy differences, so this is the sum of the protein rich system, plus the neutral rich system and then subtracting twice the excitation energy of the N equals the nucleus.
Kathrin Wimmer: And this tests this charge independence of the nuclear attack so by looking at these excitation energies, we can search for ISIS for non conserving terms and then locally and.
Kathrin Wimmer: Since the proton which system is especially for heavier gnocchi I located very close to the proton drip line.
Kathrin Wimmer: it's very difficult to study the States, so another quantity, that we can look at is the so called quantum energy difference.
Kathrin Wimmer: Which is the energy difference between the N equals D system and the nervous system, so this is easier to access experimentally in this plot here I show the column energy difference as a function of spin for various systems between mass 42 and 70 and you can see as a function of spin.
Kathrin Wimmer: The quantum energy difference rises in all these nuclei in the sd and the FP, shall we say, exception of the equal 70, I suppose, they show an anomalous behavior of the column energy difference that it goes down in energy, what are the others co op.
Kathrin Wimmer: And the initial interpretation of that what was that this is due to the week binding of the system, so in this medium happy Nokia I become very close to the proton drip line and a reduction of the coolant.
Kathrin Wimmer: repulsion between the protons due to the spatial expansion of the proton way function could explain this anomalous behavior.
Kathrin Wimmer: However, later experiments for mass 74 and 78 which are now shown here and blue and green show again a positive column energy difference, so this negative trend only occurs in the equal 70 yards towards.
Kathrin Wimmer: So the explanation of week binding cannot hold because these other systems are even closer to the product.
Kathrin Wimmer: And a tournament eternity of explanation for this is shaped change between the selenium 70 s or neutral rich system and brahma and 70, which is the acquisition of years and this would then result in a further lowering of the rest states for krypton 70 for the proton which system.
Kathrin Wimmer: So, within this experimental study we have first studied the spectroscopy of krypton 70 and we have produced tripped and 70 and several.
Kathrin Wimmer: reactions which are shown here on the left and we were able to do some first spectroscopy of this nucleus and find the excited states and.
Kathrin Wimmer: In particular, here, the two plus state and the four plus state, but then also further states only the second two plus state, and the second four plus state.
Kathrin Wimmer: We found in this react now if we compare this then with theoretically calculations which now include some ISIS non conserving interactions we see here again the column energy difference which goes down for.
Kathrin Wimmer: My 70 nuclei in green follicles up for 74 the theoretical calculation know reproduces trend in the triplet energies which you see here the results for.
Kathrin Wimmer: Also very well described by the theoretical calculations and.
Kathrin Wimmer: The experimental data that we now have four krypton 70 are these points here, and you can see that they are somewhat reproduced by the theoretical calculations, however, there are still some differences which cannot be explained.
Kathrin Wimmer: and going back to what I said previously, this I spend on conserving the actions are put into these calculations, but.
Kathrin Wimmer: Why this mass 70 system behave so differently than the others, we still do not understand, so one of the explanations that I have.
Kathrin Wimmer: discussed previously is that there's a shape change in these Nokia, so why would we expect the shape change exactly there in the mass 17 years.
Kathrin Wimmer: So this shows you the nuclear chart and in the color code is the predicted shape of the nucleus, so all the reds nuclei our product deformed and the blue.
Kathrin Wimmer: boxes indicate obligate deform nuclei and you can see in the region that we are talking about here around my 70 along the any fuzzy line there is predicted dramatic shape change between very strongly obligate and very strongly proliferate default.
Kathrin Wimmer: So it is natural to expect some shape changes in this region.
Kathrin Wimmer: Now, if you look at the krypton isotopes this time as a function of mass number.
Kathrin Wimmer: The protein rich trippin isotope show a variety of shapes this example he is taking from this publication, these are self consistent beyond mean field calculations for the potential energy surface.
Kathrin Wimmer: So on the right here, we have tripped on 74 and the potential energy surface there's a minimum on the product side and then also second minimum located here on the opposite side.
Kathrin Wimmer: And measurements of chromatic citations also verified this experimentally that's encrypted 74 we have shaped coexistence and strong shape mixing of these two States then encrypt on 72 the minimum is located here on the applied side and again column excitation measurements.
Kathrin Wimmer: are consistent versus interpretation, but then lifetime measurements also showed that there can be a transition between apply ground state and a more prolific deformed excited state and it's not rooms.
Kathrin Wimmer: We also see that there's a second minimum located here on the product side and encrypt on 72 and excited zero Plus state has discovered and the large electric monopole strengths points at a large difference of information.
Kathrin Wimmer: Now for krypton 70, this is only a prediction and that point, it is predicted that it's a blade deformed but there's also some degree of commerce of seo.
Kathrin Wimmer: So now, I will explain briefly the experimental techniques that we use to study this nuclei and to learn something what the shape.
Kathrin Wimmer: So the experiments were performed at Dr BF in Japan, and this is a fragmentation facility, where you'd be used a chain of linear accelerators and then several Cyclotron accelerators.
Kathrin Wimmer: to accelerate primary beams up to uranium up to an energy of 345 and maybe brooklyn which are then impinging on the primary reaction target to produce all kinds of exotic nuclei by project type fragmentation.
Kathrin Wimmer: So we accelerate krypton 78 primary beam was an intensity of 300 particle Nana amps up to an energy of.
Kathrin Wimmer: And then, this beam impinges on the primary reaction target and use the big rip separator in order to separate out the nuclei of interest using degrade us and bending magnets and.
Kathrin Wimmer: Then also identify the nuclear nuclear event by event using the time of flight between simulators located here at three and seven by measuring the energy loss in iron Chamber located here and by tracking the beams through the magnetic field and determining the Bureau.
Kathrin Wimmer: Then we can identify event by event the charge of the audience and the a of a Q ratio and this allows us to identify the project is of interest.
Kathrin Wimmer: Here at this f8 focus, we have a secondary reaction target where we use secondary reaction, and this is surrounded by the Dalai to gamma detector array which I will describe it in a second.
Kathrin Wimmer: Then, after the target we have these European Gary spectrometer which works by the same principle where we all again identify event by event by measuring time of flight and the energy loss, as well as the robot.
Kathrin Wimmer: The.
Kathrin Wimmer: setup at f8 looks like this the beam comes here from the Left, we first track the beam using to pack detectors where we measure the incoming trajectory.
Kathrin Wimmer: Then we have to target located at the Center and we have a second, third P pack after the target where we can measure the scattering angle.
Kathrin Wimmer: The Dolly to array is an array of sodium iodide detectors 186.
Kathrin Wimmer: which have an intrinsic energy resolution of about 7% at one a movie.
Kathrin Wimmer: So this is not very good resolution and including the position resolution the typical in beam resolution for spectroscopy at about hundred 50 movie production amongst two to 10%.
Kathrin Wimmer: So this is not very high resolution, however, this array with this compact geometry has a very large efficiency, amounting to about 10% at one movie.
Kathrin Wimmer: So this allows us to do spectroscopy of very rare nuclei was low production yet.
Kathrin Wimmer: So the experimental conditions that we have for him being gamma Ray spectroscopy at Dr BF or that we have very high primary beam intensities.
Kathrin Wimmer: And or secondary be my energy is typically around 200 maybe production, but we don't have very good energy resolution for gamma Ray spectroscopy.
Kathrin Wimmer: So the typical experiments that we do are indicated here, but the blue ellipses, and these are regions of extreme I suspend so we go to Nokia, I will show you can only produce, with a few particles per second.
Kathrin Wimmer: So we try to do first spectroscopy of these nuclei at the limits we measure collective properties, like the energies excitation energies of two plus four plus states.
Kathrin Wimmer: specifically for this talk we measure column excitation to determine the be two values and also some experiments, where we measure one response of exotic Nokia.
Kathrin Wimmer: In some cases, we could also do a knockout reactions to studies in a particle States in cases of magic nuclei where the level density is not very high, we can even so, we only have a modern resolution achieve very nice thought.
Kathrin Wimmer: So now, I want to discuss the first part of the experiment that we did discuss to shape coexistence of krypton 72.
Kathrin Wimmer: So initially this part of the experiment was.
Kathrin Wimmer: kind of a benchmark experiment to.
Kathrin Wimmer: test the analysis of column excitation experiments and prepped on 72 could be produced just very high intensity and it's also quite well known, so, especially the high spin structures were known from various fusion of operation experiments.
Kathrin Wimmer: So in this plots I show the doppler corrected gamma Ray energy spectrum for on the left side and elastic scattering on a light beryllium target and on the right side.
Kathrin Wimmer: For the scattering on a high Z go target, so the right side is dominated by column excitation while in the nuclear scattering.
Kathrin Wimmer: We populate less specifically many states, so what we see here is the big peak is the known first two plus state, and we also observe here the excitation of the four plus state.
Kathrin Wimmer: And in addition to these two known states we find for new transitions in the spectrum, which were not observed in the previous highs studies in particular this transition here at.
Kathrin Wimmer: kV is also observed in the column excitation and relativistic energies column excitation.
Kathrin Wimmer: dominance dominant Lee populates two plus states, so we can already assign this transition to the decay of an excited to second two plus state.
Kathrin Wimmer: Over this transition here at 947 kV is observed in coincidence, with this new two plus transition, so this is a candidate for an for plus state.
Kathrin Wimmer: So just by the observation of this new gamma Ray transitions we can.
Kathrin Wimmer: Not advance, we can extend the spectroscopy of krypton 72 so on the right side I show.
Kathrin Wimmer: Simplified level scheme of krypton 72 or, this is the wristband which was previously known, and this is our new newly discovered second two plus state and, second, for prostate the zero Plus date was known before from it's easier road K.
Kathrin Wimmer: And then we can analyze this level scheme by using a very simple to ban mixing model.
Kathrin Wimmer: So we describe the physical states that we observe as a mixture of a purely proliferate in red and a purely ablaze configuration here blue and he's mixing aptitudes A and B then describe our physical state terms of these intrinsic purely pro late or blood states.
Kathrin Wimmer: Now I said before, that the ground state band is very well known up to very high spin which is not shown here.
Kathrin Wimmer: But it's well known, and it is prolific deformed very high expense so using a variable moment of inertia.
Kathrin Wimmer: We can extrapolate the excitation energies of the purely proliferate deformed configurations so but like extrapolating down from high spin we obtain the energies for the purely proliferate different configurations shown here.
Kathrin Wimmer: And then we can use these pure configurations and the actual observed energies in order to determine these amplitude A and B.
Kathrin Wimmer: And this is not shown here by the colored bars for the zero Plus states, this was already previously done in this publication and this extrapolation shows you that the ground state here is dominant Lee obligate to form.
Kathrin Wimmer: Now we have these two new states two plus two and four plus tool, so we can extend this mixing model to hire spins and the result of this analysis shows you that already the.
Kathrin Wimmer: First, two plus eight is very strongly pro late, so the main amplitude here is from the product configuration and then the four plus state is almost purely product.
Kathrin Wimmer: So we have an inversion of the ordering of the States, so the ground stage is.
Kathrin Wimmer: Mainly or blade but within the ground state band is a rapid transition towards proliferate states and this interpretation is consistent with the interpretation of the p value measured for the four plus state.
Kathrin Wimmer: But then we measured the column excitation so again on the left side is the energy spectrum measured.
Kathrin Wimmer: For the column excitation go target and we have the Cross sections for these two two plus states.
Kathrin Wimmer: And by combining the analysis of the goal targeted with the analysis of the beryllium target data we can obtain the Nokia information links and the two matrix elements, using a distorted beef couple of channels calculations.
Kathrin Wimmer: So doing this self consistent analysis we obtain both the Nokia defamation, which is shown here and the column defamation, and this also very nicely described the angular distribution that we measure for the scattering of the quarter.
Kathrin Wimmer: And then, since we have so much statistics, we have to take care of all the systematics and all the theoretical uncertainties which contribute to the final uncertainty.
Kathrin Wimmer: and be obtained a pov to value for the first two plus state of 4023 was these uncertainties which is a.
Kathrin Wimmer: very nicely, in agreement with the previous measurement of relativistic limitation and also lifetime measurements and the spear V to value in in a rotational model corresponds to a Peter deformation parameter of bonds 0.3.
Kathrin Wimmer: Now for the second two plus date, this is the first time that to be true value is determined here and the value that we obtained here 665.
Kathrin Wimmer: which corresponds to a much smaller defamation of only about 0.1 so these two states clearly have different defamation and this already suggests that we have shaped coexistence of two different configurations.
Kathrin Wimmer: So we can go back to the mixing model and so far, we have only used the energies to obtain this amplitude and B and bs the amplitude of the object configuration and as the amplitude of the product configuration So these are numbers.
Kathrin Wimmer: But then, now we also have the two matrix elements and we can use the same simple mixing model to write down the matrix elements, the two matrix elements for the physical states which are here on the left.
Kathrin Wimmer: In terms of the purely ablaze or purely proliferate configurations here, you can see that this is a lot of equations and a lot of unknowns and year but.
Kathrin Wimmer: I only want you to look at the color code so obviously which is blue is our plate, and everything bridges red is the pro late, and you can see that these four equation mix of late and pull it together.
Kathrin Wimmer: Then we have to make fewer assumptions, because you see that there's a number of parameters and we have too many equations at too many unknowns to solve.
Kathrin Wimmer: All these equations So the first assumption is that the four plus states are pure and experimentally, from the excitation energies, we have already arrived at the four plus state the empty.
Kathrin Wimmer: Empty to for the four plus status is almost zero so we make the assumption that the four plus date.
Kathrin Wimmer: A four is is one, and then we can relate the matrix elements, why are the beautiful two values to the defamation, the intrinsic defamation of the opposite or the production system.
Kathrin Wimmer: So now, if you write on all these equations for the bmp to value and the electric monopole strengths, we have a bunch of factors, but then.
Kathrin Wimmer: The things here are the amplitude so the bees and the ace and the intrinsic deformation of the tablet or the product system.
Kathrin Wimmer: And again, you can see that this is is a bunch of equations which was very many unknowns moreover it's actually a fourth order equations so to solve this it's still rather complicated.
Kathrin Wimmer: So this is an equation system was many possible science, so we cannot independently solve for the information and the amplitude.
Kathrin Wimmer: So what we did, is actually using the amplitude which we have obtained by looking only at the transition energy So these are numbers that we have used before.
Kathrin Wimmer: But, looking only at the energies and then we can draw here this plot of the intrinsic product information was the intrinsic opposite information.
Kathrin Wimmer: and use the experimentally measure P two values and the electric monopole strengths to obtain constraints on the two parameters.
Kathrin Wimmer: You can see that all experimental evidence that we have points to an overlap in this region here was an intrinsic operate deformation of around 0.24 and an intrinsic prolific deformation of around 0.45.
Kathrin Wimmer: So, within this model we can describe all the States and all the transitions between the low lying states encrypt on 72.
Kathrin Wimmer: By a mixing and shape coexistence of knob late and the product configuration.
Kathrin Wimmer: Now, this is a very simple naive model, but we can also compare our results to more robust theoretical calculations.
Kathrin Wimmer: And yeah show the experiment level scheme for the zero plus two, plus states, together with the beauty two values here in comparison with.
Kathrin Wimmer: Beyond mean few calculations, using the economy and the action and the this one here is how to form of calculations mapped on five dimensional collected from Antonia.
Kathrin Wimmer: And you can see that this calculation reproduces db of it to for the decay of the first two plus state rather well, while the other beautiful values are not so well reproduced.
Kathrin Wimmer: Moreover, this calculations also over predict the energy of the excited to plus state which is co located at one and maybe while experimentally, it is found the lowest excited state krypton 72.
Kathrin Wimmer: These calculations also predict that the two plus one state is moderately applied deformed and the two plus one, two, plus two state is more strongly if.
Kathrin Wimmer: This other calculation here are symmetry conserving configuration mixing calculations which presented previously in the potential energy surface.
Kathrin Wimmer: And these calculations, as you can see predict a very much compressed level scheme, they over predicted information is too small energies and very large quattroporte moments, and at the moment, this is not fully understood, where this comes from.
Kathrin Wimmer: But So the message here is that the theoretical calculations.
Kathrin Wimmer: They more or less predict the structure of the nuclei but in the details, they clearly need some improve.
Kathrin Wimmer: But we can still look at.
Kathrin Wimmer: The way functions which the calculations predict and here, show the calculate probability density is on the left side for the.
Kathrin Wimmer: HP calculations and you see that the.
Kathrin Wimmer: Wrong state and the first two plus stage on here they are moderately obligate but then the first four plus state is predicted to be strongly pro late.
Kathrin Wimmer: And this year's for the excited state So you see that the excited to plus two, plus two state they are strongly pro a deformed and then the four plus tours is our blood, so, in agreement with what we learned from the.
Kathrin Wimmer: band mixing model this shape change along the rust States going from orbit to proliferate.
Kathrin Wimmer: In the other calculations I plot here the collective way function and they predict the similar picture for the ground state was the ground state being.
Kathrin Wimmer: Applied deformed and excited to plus it being strongly productive form but then the two plus states they're completely mixed.
Kathrin Wimmer: While the four plus States now have this change of the shape, so, in agreement with our experimental results and also other experimental results that were previously known about krypton 72 we have coexistence and shape change along the rest.
Okay.
Kathrin Wimmer: So let me now come to the second part, which is the title of the talk, namely the shapes of the mirror Nokia 70 selenium and 70 krypton.
Kathrin Wimmer: So let me go back to the motivation so we're looking at this T equals one states and.
Kathrin Wimmer: We want to study I suspend symmetry and I suspend independence and typically there's a standby spectroscopy of analog states certain begin.
Kathrin Wimmer: So, by looking at these mirror and triplet energy differences, but these energies, they do not really probe the way function.
Kathrin Wimmer: So there's an alternative way to test I suspend symmetry by looking at multiple matrix elements, so the proton or the neutron matrix elements which involves the way function of the states can be accessed through the bmp two values.
Kathrin Wimmer: And if you write this proton neutron matrix elements in an ISIS been representation, with an ISIS Gala and I vector matrix element m zero and one then if we assume I suspend symmetry the proton matrix element which can be determined from the beefy to value.
Kathrin Wimmer: is just a linear function of cheesy so it's an ice skater miles select pod.
Kathrin Wimmer: So by measuring the pov to while use, we can test this linear relationship of the protein matrix.
Kathrin Wimmer: So here show a couple of examples for lighter nuclei between mass 72 and 42 as 22 and 42.
Kathrin Wimmer: which have been studied in the past, and you can also see that the.
Kathrin Wimmer: The experimental data points are lying on the line so.
Kathrin Wimmer: The protein matrix element is linear in tz however there's no data on tz minus one so proton which nuclei beyond mass 54.
Kathrin Wimmer: And in all these cases, there are different experimental setups and different experimental techniques used for the different ice Abbas.
Kathrin Wimmer: So there's some different systematic uncertainties so in order to test this better, we need more consistent approach and measure the three nuclei involved in a consistent way was consistent systematics.
Kathrin Wimmer: So the first.
Kathrin Wimmer: case where the assessment studied in a more rigorous way is the mass.
Kathrin Wimmer: 46 nuclei so chromium within a demon titanium and in this measurement which was performed the gci.
Kathrin Wimmer: The titanium.
Kathrin Wimmer: 46 and chromium 46 nuclei were measured by column excitation and then the radium here and again the less exotic titanium were measured.
Kathrin Wimmer: By a lifetime measurement using a stretch target, and you can see the experimental results you can read, together with a linear fit shows the lie nice D on the line.
Kathrin Wimmer: The green and blue or shorter calculations which also linear and they make different assumptions about.
Kathrin Wimmer: The effective charges, but in general the absolute magnitude until the narrative cerebral reproduced in this case.
Kathrin Wimmer: Now, if you want to test for linear This is one can fit the proton matrix and a month results by a quadratic function.
Kathrin Wimmer: So, instead of just having a linear function of tz a quadratic term is added here, and he has shown this the coefficient of the quadratic term as a function of the mass number of the system, and you can see that this see term is basically zero for these cases and.
Kathrin Wimmer: suggests that the protein matrix elements is linear and this is the first case where and consistent experimental approach is used to study the three nuclei and the systematic uncertainties are under control.
Kathrin Wimmer: So this motivates us to look at the column excitation of krypton 70 and to test the linearity of the proton matrix element for this case where we have this anomalous behavior of the column energy differences and potential shape changes.
Kathrin Wimmer: So here is the energy spectrum the doppler corrected energy spectrum for krypton 17 measured again with go target, and you can see, in.
Kathrin Wimmer: comparison to krypton 72 which show before we add much reduced statistics because there's no cure is this very, very exotic and the production, here it is very, very low.
Kathrin Wimmer: But we observed, clearly the transition here at 884 kV.
Kathrin Wimmer: and using again the same approach of a consistent analysis of the.
Kathrin Wimmer: data that we took was like target and the goal target we can determine the nuclear deformation links 0.22.
Kathrin Wimmer: and also the be a free tool value now, in this case, we also have to make some feeding corrections which we have estimated from neighboring Nokia and also theoretically calculation and this contributes to all systematic and also.
Kathrin Wimmer: theoretical uncertainty, so this this radical uncertainty comes mostly from the reaction modeling we do.
Kathrin Wimmer: But this analysis, gives us a defamation parameter determined from the be to have 0.25.
Kathrin Wimmer: So, before I discuss the mirror symmetry I just want to briefly discuss the evolution along the krypton isotopes and show the or results.
Kathrin Wimmer: make sense, with the theoretical calculations and what is known from the systematics so on the left is to be a fee to value as a function of the mass number for the crypto lucky I, and this is all crypto and 72 which is shot before, and this is our new measurement for krypton 70.
Kathrin Wimmer: And these are here, compared with several theoretical models.
Kathrin Wimmer: The.
Kathrin Wimmer: Blue one is is the hot glue of calculations was the fifth dimensional collected from Antonio which I showed before and they very nice to reproduce the trend of the krypton isotopes for two plus states, and also the four plus states which are shown here.
Kathrin Wimmer: As I said before, for the two plus two and there's some discrepancies between the experimental results in this model.
Kathrin Wimmer: The green line is the symmetry conserving configuration mixing model, which also showed before they over predict the collectivity as a set, but the trend of the krypton isotopes is still very nicely predicted.
Kathrin Wimmer: And then, lastly, in black and in red I show some show model calculations, but these are shorter calculations which are only in the FP Shell and obviously this the model spaces were much to restricted in order to capture the the collectivity of smoking.
Okay.
Kathrin Wimmer: So let's discuss the matrix elements that we have obtained for this mass 17 UPI.
Kathrin Wimmer: And in order to make the comparison within the triplet, we have to very carefully analyze all the systematic and theoretical or reaction model uncertainties.
Kathrin Wimmer: So here I show no to spectra of bro mine 70 and selenium 68.
Kathrin Wimmer: Which are previous you know and which we have measured in the very same setting at the very same time as strict on 70.
Kathrin Wimmer: So this we use as a benchmark for analysis we observe the excitation of the two plus data and bro mine 70 and for selenium 70 we have a lot of statistics that we even could observe, as you can see here in the log scale the excitation of the second two plus data.
Kathrin Wimmer: So by comparing our measurements, which are shown here by the blue dots for the different isotopes that we had in our reaction setting.
Kathrin Wimmer: With all the previous measurement which are shown by the black dots we are quite confident in our analysis.
Kathrin Wimmer: And you can see that for most cases the statistical uncertainties smaller than the dots only for the selenium seven T, which was at the edge of the acceptance, we have a quite large.
Kathrin Wimmer: Statistical uncertainty, but the main sources of the uncertainty and all the other cases are coming from systematics and from the.
Kathrin Wimmer: theoretical calculations.
Kathrin Wimmer: But this measurements of of the neighboring and apply validates our analysis procedure and we have a consistent measurements for all members of the triplets so we have to borrow mine and we also have the selenium and where we reproduce the previous measurements.
Kathrin Wimmer: So let's now look at the linearity of the matrix elements.
Kathrin Wimmer: And this plot a show the protein matrix elements as a function of the I suspend and these thoughts here are the weighted average is of the previous measurements for us Roman 70 and selenium 70 so if we just fit this with a line.
Kathrin Wimmer: In this.
Kathrin Wimmer: Then we obtained for the protein matrix element ISO scale matrix element of 76 and as a vector of minus six so there's a negative trend.
Kathrin Wimmer: In this protein matrix element so maybe this seems a bit unusual you might expect that the proton rich or the the more protons, you have the larger the matrix elements.
Kathrin Wimmer: But this has been studied before in the study.
Kathrin Wimmer: Published here for various nuclei between us 2274 and you can see the black dots here our scale a matrix elements and the red.
Kathrin Wimmer: triangles or the vector and you can see the I vector they are very small, so this means that this line is almost horizontal and for the heavier nuclei which you can see here and negative, they also negative so a negative trend is not so unexpected this case.
Kathrin Wimmer: So next we can extrapolate this linear relationship to.
Kathrin Wimmer: T minus one so to our krypton 70 and just a linear extrapolation of that would result in a matrix element of so define a script.
Kathrin Wimmer: So this is what we would expect if we only know these two nuclei So if I now show what we actually measure.
Kathrin Wimmer: You know, so this is all measurement for krypton 70 and you can see the measured.
Kathrin Wimmer: Or the protein matrix element extracted from our view of the true value deviates by three Sigma from this linear extrapolation the there's a clear sign for a deviation from I suspend symmetry observed in this age of 70 triplet.
Kathrin Wimmer: So let's look at the shape of these nuclei So what we know about the shapes of equal 70.
Kathrin Wimmer: I spin triplet is not so much maybe.
Kathrin Wimmer: silly selenium 70 has been studied before and there has been a column excitation measurement which gives you the view of the true value but also it depends on the quarter for a moment, so this blue pants here shows the correlation obtained from the column excitation at low energies.
Which.
Kathrin Wimmer: alone, the low energy column excitation measurement alone does not allow you to extract up to value or the quarter for a moment, however lifetime measurement, which is only sensitive to the beauty to value gives you this red band, and the overlap is here on the opposite side so.
Kathrin Wimmer: In agreement with theoretical calculations selenium 70 is selected for.
Kathrin Wimmer: Now, if we assume I suspend symmetry, then the States should have the same way function, so we would also expect the operator formation for krypton 70.
Kathrin Wimmer: So we can look at theoretical calculations, and this is a bit busy plot, but, as before, this is the proton matrix element as a function of ISIS spin and the red dots here all measurement and then some previous measurement for the nuclei.
Kathrin Wimmer: Compared with various theoretical calculations which you can see, in blue and green.
Kathrin Wimmer: Now this these calculations or predict ability formation for selenium 70 and also for krypton 70, with the exception of this vampire calculations which predict the shape mix.
Kathrin Wimmer: but also all these calculations also only predict a small increase in.
Kathrin Wimmer: The matrix element.
Kathrin Wimmer: For krypton 70 compared to selenium 70.
Kathrin Wimmer: With the exception of this show model calculations which is too small model space.
Kathrin Wimmer: So the.
Kathrin Wimmer: T theoretically calculations predict only a moderate increase in.
Kathrin Wimmer: In the proton matrix element, and if we interpret the protein matrix element, or the pov to value in a rotational model we can link it to the defamation parameter Peter so a larger V2 value obtained for krypton 70 suggests more defamation.
Kathrin Wimmer: So we have a shape change in this mirror nuclei between selenium 70 and krypton 70 where the krypton 70 is significantly more deformed and selenium 70.
Kathrin Wimmer: So to summarize the results here the equal 70 nucleus is now the heaviest ISIS been triplet we're all of the three be free to use our experimentally known.
Kathrin Wimmer: The dmv to value of krypton 70 is significantly larger than in the mirror nucleus selenium 70 and it deviates by three Sigma from the linear extrapolation of the proton matrix element.
Kathrin Wimmer: So.
Kathrin Wimmer: there's a number of suggestions that we can make of why this is the case, first of all.
Kathrin Wimmer: We can think about an ISIS been mixing of T equals zero and T equals one State and bro mine certainty.
Kathrin Wimmer: Now there's no clothes lying two plus two state known in Rome and 70.
Kathrin Wimmer: So it's a bit difficult to explain this by ISIS been mixing more over this large increase of the connectivity between selenium and krypton cannot be explained by ISIS been mixing.
Kathrin Wimmer: So an alternative would be to discuss the shape change between the mirror nuclei of selenium and krypton so one option is that the krypton 70 is prolific formed.
Kathrin Wimmer: Now, from our experiment, we have no measure about the sign of the defamation, we can only tell the triptans more deformed.
Kathrin Wimmer: So Ideally, we would like to do a low energy column excitation experiment, similar to what has been done for selenium 70, however, was the present beam intensities, this is a bit out of reach.
Kathrin Wimmer: So, at the moment it stays like this that we, we have to say that the shape of krypton 70 is definitely different than selenium 70 but whether we have changed from update to pro late, we cannot say.
Kathrin Wimmer: So.
Kathrin Wimmer: In the beginning i've told you that the math 70 system is a bit peculiar and the column energy differences are very much different than all the other.
Kathrin Wimmer: I suspect triplets that have been studied, so the next logical question is to study, what about other medium mass at equals one trip that's.
Kathrin Wimmer: And for that we have performed the new experiment, where we want to constrain the systematic uncertainties as much as possible.
Kathrin Wimmer: So in many of the previous experiments that have shown the systematic uncertainties came from different measurements using different techniques like quantum excitation or.
Kathrin Wimmer: lifetime measurements, but we want to use the identical absolutely identical experimental technique and.
Kathrin Wimmer: Experimental conditions for all three members of a triplet This way we can cancel all the systematic uncertainties and really precisely test the ISIS been symmetry so in this new experiment, we were not focusing on mass 62.
Kathrin Wimmer: And we were using the same target the same energy, the same detector the same setting everything absolutely identical in order to constrain all the systematic uncertainties.
Kathrin Wimmer: This plot here shows you the energy spectrum that we have obtained, nor for.
Kathrin Wimmer: zinc 62 gallium 62 and germanium 62.
Kathrin Wimmer: If I normalize the counts for number of incident particulates.
Kathrin Wimmer: We don't have the Cross sections, yet you have to.
Kathrin Wimmer: be a bit more patient, but you can see that the germanium and the sink they look almost the same so could can already say that the PFC two values will be very similar.
Kathrin Wimmer: The guy zoom and shown in red is is lower, but this is just normalized for incident been particles and we have to very, very carefully correct the transmission, which is affecting the sky Liam.
Kathrin Wimmer: beam a lot so from this plot, you cannot read off that guy up to value is much lower than the other two.
Kathrin Wimmer: This analysis is presently done by a typhoon or the sick, but what we anticipate from this measurement is that for relative protein matrix element, we could get an uncertainty.
Kathrin Wimmer: of a few percent and this allows us really to do a position tests of ISIS symmetry with very exotic radioactive beams.
Kathrin Wimmer: OK so Now I come to summary of my talk i've shown you one example, where we have very high primary beam intensities which allow us at the rbs to study nuclei located very close to the drip lines.
Kathrin Wimmer: In this specific case we investigated ISIS been symmetry and shape transitions around krypton 70.
Kathrin Wimmer: i've shown you our results for the extended spectroscopy of krypton 72 which show a transition from obligate the formation in the ground state to proliferate deformed.
Kathrin Wimmer: excited state in the column excitation measurement that we have performed via found a second shape coexisting less deformed proliferate.
Kathrin Wimmer: Two plus two stage, and we can describe all of our data for the low lying state by a very simple to ban mixing model which mixes proliferate and apply configurations to obtain the physical state.
Kathrin Wimmer: Then i've shown you our study of I suspend symmetry.
Kathrin Wimmer: Looking at the multiple matrix elements and the.
Kathrin Wimmer: value that we have obtained from krypton 70 is very much different than what one would expect from the linear I suspend conserving trend, so this suggests that we have some I spin violation, they are.
Kathrin Wimmer: More what is a very large increase in the bfa to value in krypton 70 compared to selenium and this suggests that these two lucky, I have a different shape.
Kathrin Wimmer: Was that I want to thank all of this collaboration and thank you for your attention.
James Smallcombe: Thank you very much country that was fantastic.
James Smallcombe: So yes, if we have any questions, please can you head on down that participants menu and click the raise hand button, I see this to collapse flowing in.
James Smallcombe: But also, as I said before, if you don't have a microphone you can put your questions in the chat box and i'll be happy to read those out for you.
James Smallcombe: jack Henderson please you want to unmute and go ahead with your question.
Jack Henderson: I got ring hello, thank you, that was it was really nice that he has been unbelievably good.
Jack Henderson: terrifyingly so um I have a couple of questions for the 72 script on Do you see any indication of the decay of the new two plus State to the other, the zero Plus, or the excited or across all the exotic to yes.
Kathrin Wimmer: So I.
Kathrin Wimmer: know this.
Kathrin Wimmer: But we have here.
Kathrin Wimmer: coincidences and so okay.
Kathrin Wimmer: This is the same spectrum as a show before doppler corrected energy for the beryllium target, and if you zoom in on this region year.
Kathrin Wimmer: There is an indication for another transition here at 434 kV which matches the decay, to the.
Kathrin Wimmer: Two plus state.
Jack Henderson: Nothing to the nothing to the zero Plus.
Kathrin Wimmer: No, I mean this this actually is only an upper limit from this, you see that the background goes up.
Kathrin Wimmer: resolution is not very good, we have an upper limit, I do not remember the number exactly, but we have an upper limit, also for the decay, to the zero Plus, but we don't we don't see it.
Jack Henderson: For the equal 70 triplet um.
Jack Henderson: I think I think it's it's now relatively well established that the Channel calculations don't get aren't going to get the shapes right at that point, because they they can't feasibly have a large enough model space.
Jack Henderson: I can't remember exactly I think I think I think anything above anything selenium and higher requires including.
Jack Henderson: Basically i'm physically left, so I don't know it isn't necessarily unexpected that the.
Jack Henderson: The krypton selenium ratio is so different because to my eye looks more like the show model calculations are basically doing all right for the krypton and selenium but are kind of completely screwing up the bromine rather than the other way around.
Jack Henderson: And I think that that would almost be more this one, you say yeah let me show no calculations get the gradient almost correct once you consider the lead sorry there's 145.
Jack Henderson: That kind of decent model space once you consider the fact that it's it's not incorporating all of the the defamation driving orbitals because it can't.
Jack Henderson: It almost looks like it's getting the gradient about right, whereas the bromine is completely off by all reasonable kind of calculations right, I mean I just it's not I don't know.
Jack Henderson: I can't think of anything off the top my head that would explain it but.
Kathrin Wimmer: Yes, so you're right, so I mean all these calculations predict a slight upward trend, but.
Kathrin Wimmer: None of the calculations really.
Kathrin Wimmer: fits what what we observe yes.
Jack Henderson: Yes.
Jack Henderson: Yes, I just i'm not i'm not sure i'm.
Jack Henderson: Not necessarily sure you would expect them to perfectly do it because of the failures in the middle of the inadequacies of the model space i'd be, I think that it almost looks like the Berman, is the more interesting.
Jack Henderson: One in the it clearly is behaving differently to the to all of the model expectations, but I guess that's.
Jack Henderson: Yes, almost.
Kathrin Wimmer: Almost.
Kathrin Wimmer: All the models, except for this one, which is not really, this is just a mean field.
Kathrin Wimmer: calculations were took the beta and converted them to be able to, but all these calculations are linear so none of them can predict such a deviation yeah.
Jack Henderson: I mean when you're when you're looking at 333 points with a straight line and there's only limited away so you can construct it yeah Okay, thank you very much.
James Smallcombe: You have any other questions.
James Smallcombe: Is that people think is okay, please go ahead.
isacker: yeah okay thanks very much was very nice I hit you showed at some point.
isacker: triplet it in the D show.
isacker: And it seemed to me that there was also another anomalous case.
Kathrin Wimmer: Is one year was.
isacker: 38 so, can you comment on that too.
Kathrin Wimmer: So that this is one of the cases which has been measured with different techniques.
isacker: So you think it's an experimental problem don't line up on a straight line that's.
Kathrin Wimmer: i'm i'm not so sure it should be revisited also, in this case.
Kathrin Wimmer: The.
Kathrin Wimmer: It is it's experimentally certificate, so you cannot do this in quantum excitation for the T equals zero.
Kathrin Wimmer: Because the ground state is not zero so it's a transition between excited states.
Kathrin Wimmer: Yes, in this case there's also a deviation but.
Kathrin Wimmer: So.
Kathrin Wimmer: experimentally, I think this should be, it should be investigated again.
Kathrin Wimmer: The the authors of this publication also discuss this as a case of ISIS been mixing.
isacker: Because, in this case, I think there are two other closely Line two plus states, yes, the.
isacker: nucleus, yes.
isacker: In, so this is not the case in the in the mass 70 right.
Kathrin Wimmer: Yes, there's there's no candidate known, there are many states known and bro mine 17 but there's there's no candidate for another two plus state.
isacker: Okay.
Kathrin Wimmer: But one should also search for that.
isacker: Okay, thank you.
James Smallcombe: Okay last question here, would you like to go ahead.
Hu Baishan: yeah can you hear me yes Okay, thank you very much, have a nice to have a question about a theory, so I know some Tomas Armor sheet tear for the.
Hu Baishan: weekly bounded nuclear.
Hu Baishan: behavior we are different to for the ISIS been symmetry I don't know for the Curry Curry turn.
Hu Baishan: This effective it's.
Hu Baishan: Important or not, because the looks the same the proton reach nuclear so I don't know for the key to this different amazingly from the proton we click on the behavior or old older seem Chamberlain symmetry as being symmetry pre K factor.
Kathrin Wimmer: So, as I discussed in the beginning, the the quantum energy different anomalous behavior of the colon energy difference was initially interpreted as.
Kathrin Wimmer: As resulting from vic binding.
mm hmm.
Kathrin Wimmer: Because it's very close to close to the proton program drip line, but then the heavier nuclei were measured.
Kathrin Wimmer: And they did not show now, it would obviously be very interesting to go to 74 and measure the view of the two values.
Kathrin Wimmer: and
Kathrin Wimmer: I would be very happy to to try this but experimentally it, it will be very, very challenging.
Kathrin Wimmer: The krypton 70 was already very low beam intensity.
Kathrin Wimmer: The advantages that you can produce it from a krypton primary beam so you just remove neutrons to make it so if you go up.
Kathrin Wimmer: And would try to measure column excitation for 74 you would have to add protons or you would have to start with a heavier primary beam so experimentally, I think column excitation measurement is very challenging.
Kathrin Wimmer: But they will be definitely interesting and it could address exactly this question.
Hu Baishan: Okay okay Thank you all have a very quick question another if you tried some IP initial calculation, because I thought the inferior calculation and the model calculation I don't know for the initial calculation, I think I can you their hand those is.
Kathrin Wimmer: Not for this look shy, because this is nuclei are known to be default and up Initial calculations are are just starting to get into the calculation of the form nuclei invited systems up Initial calculations have been applied for studies of Pfizer spin symmetry.
Hu Baishan: OK.
Hu Baishan: OK OK, thank you.
James Smallcombe: Okay, at this point, I like to welcome anybody who has problems with the raise hand function to unmute yourself if you have a question and just go ahead.
James Smallcombe: I don't see any questions in the chat.
James Smallcombe: And I don't see oh there we go one more question George Please go ahead, go dunia.
James Smallcombe: towards you unmute yourself and ask your question.
George O'Neill: I do, yes, rather than just talking to myself and I have you submitted a proposal for the 70 krypton and I actually don't know if you can produce it and, for example, I sold it and we did try and do some low energy electron 70 selenium and a couple of years ago and the youth were.
George O'Neill: Not great it's really hard areas.
George O'Neill: But i'm able to juice.
George O'Neill: 70 crypto or not.
Kathrin Wimmer: So I know about your attempt, I also know that krypton 72 has been attempted several times that is already.
here.
George O'Neill: and
Kathrin Wimmer: I do not know, maybe somebody else in the audience can comment more but statistics are not very much so, if krypton 72 is.
Kathrin Wimmer: Just feasible or 10 krypton 70.
Kathrin Wimmer: is very difficult very, very difficult, it would be fantastic to measure crips on 70 was low energy cool X.
Kathrin Wimmer: But not soon.
George O'Neill: I guess.
James Smallcombe: Okay does anybody have any other questions or anyone want to volunteer knowledge of isola yields.
James Smallcombe: Otherwise Okay, I think we'll we'll call it to a close, there so i'll say thank you once again catrin for.
James Smallcombe: showing us the results.
James Smallcombe: Understanding staying up so late to answer all our questions No problem.
Kathrin Wimmer: Thank you very much, was a pleasure.
James Smallcombe: And Thank you everyone in our audience for coming and joining us, I hope, you'll join us next week same time 3pm GMT on Monday, the eighth when we have Alexandra data from Ms you who's going to be talking.
James Smallcombe: About Indian gamma Ray spectroscopy with path beams of grass tops and if you enjoyed this talk i'm sure you'll enjoy the one next week.
James Smallcombe: Okay, so that's all have a good week, thank you very much.
bye for now.