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Author Van Isacker, P.; Algora, A.; Vitéz-Sveiczer, A.; Kiss, G.G.; Orrigo, S.E.A.; Rubio, B.; Aguilera, P.
Title Gamow-Teller Beta Decay and Pseudo-SU(4) Symmetry Type Journal Article
Year 2023 Publication Symmetry-Basel Abbreviated Journal Symmetry-Basel
Volume 15 Issue 11 Pages 2001 - 15pp
Keywords Gamow-Teller beta decay; pseudo-SU(4) symmetry; odd-odd N = Z nuclei
Abstract We report on recent experimental results on beta decay into self-conjugate ( N = Z) nuclei with mass number 58 <= A <= 70. Super-allowed b decays from the J(pi) = 0(+) ground state of a Z = N + 2 parent nucleus are to the isobaric analogue state through so-called Fermi transitions and to J(pi) = 1(+) states by way of Gamow-Teller (GT) transitions. The operator of the latter decay is a generator of Wigner's SU(4) algebra and as a consequence GT transitions obey selection rules associated with this symmetry. Since SU(4) is progressively broken with increasing A, mainly as a consequence of the spinorbit interaction, this symmetry is not relevant for the nuclei considered here. We argue, however, that the pseudo-spin-orbit splitting can be small in nuclei with 58 <= A <= 70, in which case nuclear states exhibit an approximate pseudo-SU(4) symmetry. To test this conjecture, GT decay strength is calculated with use of a schematic Hamiltonian with pseudo-SU(4) symmetry. Some generic features of the GT beta decay due to pseudo-SU(4) symmetry are pointed out. The experimentally observed GT strength indicates a restoration of pseudo-SU(4) symmetry for A = 70.
Address (down) [Van Isacker, Piet] CEA, DRF, Grand Accelerateur Natl Ions Lourds GANIL, CNRS,IN2P3, Blvd Henri Becquerel, F-14076 Caen, France, Email: isacker@ganil.fr;
Corporate Author Thesis
Publisher Mdpi Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes WOS:001114520800001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5843
Permanent link to this record
 
 
Author van Beekveld, M.; Beenakker, W.; Caron, S.; Kip, J.; Ruiz de Austri, R.; Zhang, Z.Y.
Title Non-standard neutrino spectra from annihilating neutralino dark matter Type Journal Article
Year 2023 Publication Scipost Physics Core Abbreviated Journal SciPost Phys. Core
Volume 6 Issue 1 Pages 006 - 23pp
Keywords
Abstract Neutrino telescope experiments are rapidly becoming more competitive in indirect de-tection searches for dark matter. Neutrino signals arising from dark matter annihilations are typically assumed to originate from the hadronisation and decay of Standard Model particles. Here we showcase a supersymmetric model, the BLSSMIS, that can simulta-neously obey current experimental limits while still providing a potentially observable non-standard neutrino spectrum from dark matter annihilation.
Address (down) [van Beekveld, Melissa] Univ Oxford, Rudolf Peierls Ctr Theoret Phys, Clarendon Lab, Parks Rd, Oxford OX1 3PU, England, Email: melissa.vanbeekveld@physics.ox.ac.uk;
Corporate Author Thesis
Publisher Scipost Foundation Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes WOS:000928492200001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5480
Permanent link to this record
 
 
Author van Beekveld, M.; Caron, S.; Hendriks, L.; Jackson, P.; Leinweber, A.; Otten, S.; Patrick, R.; Ruiz de Austri, R.; Santoni, M.; White, M.
Title Combining outlier analysis algorithms to identify new physics at the LHC Type Journal Article
Year 2021 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 09 Issue 9 Pages 024 - 33pp
Keywords Phenomenological Models; Supersymmetry Phenomenology
Abstract The lack of evidence for new physics at the Large Hadron Collider so far has prompted the development of model-independent search techniques. In this study, we compare the anomaly scores of a variety of anomaly detection techniques: an isolation forest, a Gaussian mixture model, a static autoencoder, and a beta-variational autoencoder (VAE), where we define the reconstruction loss of the latter as a weighted combination of regression and classification terms. We apply these algorithms to the 4-vectors of simulated LHC data, but also investigate the performance when the non-VAE algorithms are applied to the latent space variables created by the VAE. In addition, we assess the performance when the anomaly scores of these algorithms are combined in various ways. Using supersymmetric benchmark points, we find that the logical AND combination of the anomaly scores yielded from algorithms trained in the latent space of the VAE is the most effective discriminator of all methods tested.
Address (down) [van Beekveld, Melissa] Clarendon Lab, Rudolf Peierls Ctr Theoret Phys, 20 Pks Rd, Oxford OX1 3PU, England, Email: mcbeekveld@gmail.com;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000695421600003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4973
Permanent link to this record
 
 
Author van Beekveld, M.; Caron, S.; Ruiz de Austri, R.
Title The current status of fine-tuning in supersymmetry Type Journal Article
Year 2020 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 01 Issue 1 Pages 147 - 41pp
Keywords Supersymmetry Phenomenology
Abstract In this paper, we minimize and compare two different fine-tuning measures in four high-scale supersymmetric models that are embedded in the MSSM. In addition, we determine the impact of current and future dark matter direct detection and collider experiments on the fine-tuning. We then compare the low-scale electroweak measure with the high-scale Barbieri-Giudice measure. We find that they reduce to the same value when the higgsino parameter drives the degree of fine-tuning. We also find spectra where the high-scale measure turns out to be lower than the low-scale measure. Depending on the high-scale model and fine-tuning definition, we find a minimal fine-tuning of 3-38 (corresponding to O(10-1)%) for the low-scale measure, and 63-571 (corresponding to O(1-0.1)%) for the high-scale measure. We stress that it is too early to conclude on the fate of supersymmetry, based only on the fine-tuning paradigm.
Address (down) [van Beekveld, Melissa; Caron, Sascha] Radboud Univ Nijmegen, Theoret High Energy Phys, Heyendaalseweg 135, NL-6525 AJ Nijmegen, Netherlands, Email: mcbeekveld@gmail.com;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000512011100001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4275
Permanent link to this record
 
 
Author van Beekveld, M.; Beenakker, W.; Caron, S.; Peeters, R.; Ruiz de Austri, R.
Title Supersymmetry with dark matter is still natural Type Journal Article
Year 2017 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 96 Issue 3 Pages 035015 - 7pp
Keywords
Abstract We identify the parameter regions of the phenomenological minimal supersymmetric standard model (pMSSM) with the minimal possible fine-tuning. We show that the fine-tuning of the pMSSM is not large, nor under pressure by LHC searches. Low sbottom, stop and gluino masses turn out to be less relevant for low fine-tuning than commonly assumed. We show a link between low fine-tuning and the dark matter relic density. Fine-tuning arguments point to models with a dark matter candidate yielding the correct dark matter relic density: a bino-higgsino particle with a mass of 35-155 GeV. Some of these candidates are compatible with recent hints seen in astrophysics experiments such as Fermi-LAT and AMS-02. We argue that upcoming direct search experiments, such as XENON1T, will test all of the most natural solutions in the next few years due to the sensitivity of these experiments on the spin-dependent WIMP-nucleon cross section.
Address (down) [van Beekveld, Melissa; Beenakker, Wim; Caron, Sascha] Radboud Univ Nijmegen, Fac Sci, Inst Math Astrophys & Particle Phys, Mailbox 79,POB 9010, NL-6500 GL Nijmegen, Netherlands, Email: mcbeekveld@gmail.com;
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2470-0010 ISBN Medium
Area Expedition Conference
Notes WOS:000407779600004 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3246
Permanent link to this record
 
 
Author Valiente-Dobon, J.J.; Poves, A.; Gadea, A.; Fernandez-Dominguez, B.
Title Broken mirror symmetry in S-36 and Ca-36 Type Journal Article
Year 2018 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 98 Issue 1 Pages 011302 - 5pp
Keywords
Abstract Shape coexistence is a ubiquitous phenomenon in the neutron-rich nuclei belonging to (or sitting at the shores of) the N = 20 island of inversion (IoI). Exact isospin symmetry predicts the same behavior for their mirrors and the existence of a proton-rich IoI around Z = 20, centered in the (surely unbound) nucleus Ca-32. In this article we show that in Ca-36 and S-36, Coulomb effects break dramatically the mirror symmetry in the excitation energies due to the different structures of the intruder and normal states. The mirror energy difference (MED) of their 2(+) states is known to be very large at – 246 keV. We reproduce this value and predict the first excited state in Ca-36 to be a 0(+) at 2.7 MeV, 250 keV below the first 2(+). In its mirror S-36 the 0(+) lies at 55keV above the 2(+) measured at 3.291 MeV. Our calculations predict a huge MED of -720 keV, that we dub the “colossal” mirror energy difference. A possible reaction mechanism to access the O-2(+) in Ca-36 will be discussed. In addition, we theoretically address the MEDs of the A = 34, T = 3 and A = 32, T = 4 mirrors.
Address (down) [Valiente-Dobon, J. J.] Ist Nazl Fis Nucl, Lab Nazl Legnaro, Legnaro, Italy
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9985 ISBN Medium
Area Expedition Conference
Notes WOS:000439059400001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3661
Permanent link to this record
 
 
Author Valiente-Dobon, J.J. et al; Egea, J.; Huyuk, T.; Gadea, A.; Aliaga, R.; Jurado-Gomez, M.L.; Perez-Vidal, R.M.
Title NEDA-NEutron Detector Array Type Journal Article
Year 2019 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 927 Issue Pages 81-86
Keywords NEDA; Nuclear structure; Gamma-ray spectroscopy; Neutron detector; Liquid scintillator; Digital electronics; Neutron-gamma discrimination
Abstract The NEutron Detector Array, NEDA, will form the next generation neutron detection system that has been designed to be operated in conjunction with gamma-ray arrays, such as the tracking-array AGATA, to aid nuclear spectroscopy studies. NEDA has been designed to be a versatile device, with high-detection efficiency, excellent neutron-gamma discrimination, and high rate capabilities. It will be employed in physics campaigns in order to maximise the scientific output, making use of the different stable and radioactive ion beams available in Europe. The first implementation of the neutron detector array NEDA with AGATA 1 pi was realised at GANIL. This manuscript reviews the various aspects of NEDA.
Address (down) [Valiente-Dobon, J. J.; Jaworski, G.; Goasduff, A.; Egea, J.; Modamio, V; de Angelis, G.; Bissiato, E.; Carturan, S.; Cocconi, P.; Conventi, D.; Deltoro, J. M.; Hadynska-Klekn, K.; Illan, A.; Raggio, A.; Siciliano, M.; Zanon, I] Ist Nazl Fis Nucl, Lab Nazl Legnaro, Legnaro, Italy, Email: valiente@lnl.infn.it
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000462142700010 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3956
Permanent link to this record
 
 
Author Valiente-Dobon, J.J. et al; Gadea, A.; Algora, A.
Title Manifestation of the Berry phase in the atomic nucleus Pb-213 Type Journal Article
Year 2021 Publication Physics Letters B Abbreviated Journal Phys. Lett. B
Volume 816 Issue Pages 136183 - 5pp
Keywords
Abstract The neutron-rich Pb-213 isotope was produced in the fragmentation of a primary 1 GeV A U-238 beam, separated in FRS in mass and atomic number, and then implanted for isomer decay gamma-ray spectroscopy with the RISING setup at GSI. A newly observed isomer and its measured decay properties indicate that states in Pb-213 are characterized by the seniority quantum number that counts the nucleons not in pairs coupled to angular momentum J = 0. The conservation of seniority is a consequence of a geometric phase associated with particle-hole conjugation, which becomes observable in semi-magic nuclei where nucleons half-fill the valence shell. The gamma-ray spectroscopic observables in Pb-213 are thus found to be driven by two mechanisms, particle-hole conjugation and seniority conservation, which are intertwined through a Berry phase.
Address (down) [Valiente-Dobon, J. J.; Gottardo, A.; de Angelis, G.; Goasduff, A.; Napoli, D. R.; Sahin, E.] Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy, Email: javier.valiente@lnl.infn
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0370-2693 ISBN Medium
Area Expedition Conference
Notes WOS:000647421500054 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4820
Permanent link to this record
 
 
Author AGATA Collaboration (Valiente-Dobon, J.J. et al); Perez-Vidal, R.M.; Blasco Miquel, J.; Civera, J.V.; Gadea, A.
Title Conceptual design of the AGATA 2 pi array at LNL Type Journal Article
Year 2023 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 1049 Issue Pages 168040 - 14pp
Keywords AGATA spectrometer; LNL facility; gamma-ray tracking; Pulse shape analysis; PRISMA spectrometer; EUCLIDES detector; DANTE detector; TRACE detector; Plunger device
Abstract The Advanced GAmma Tracking Array (AGATA) has been installed at Laboratori Nazionali di Legnaro (LNL), Italy. In this installation, AGATA will consist, at the beginning, of 13 AGATA triple clusters (ATCs) with an angular coverage of 1n,and progressively the number of ATCs will increase up to a 2 pi angular coverage. This setup will exploit both stable and radioactive ion beams delivered by the Tandem-PIAVE-ALPI accelerator complex and the SPES facility. The new implementation of AGATA at LNL will be used in two different configurations, firstly one coupled to the PRISMA large-acceptance magnetic spectrometer and lately a second one at Zero Degrees, along the beam line. These two configurations will allow us to cover a broad physics program, using different reaction mechanisms, such as Coulomb excitation, fusion-evaporation, transfer and fission at energies close to the Coulomb barrier. These setups have been designed to be coupled with a large variety of complementary detectors such as charged particle detectors, neutron detectors, heavy-ion detectors, high-energy gamma-ray arrays, cryogenic and gasjet targets and the plunger device for lifetime measurements. We present in this paper the conceptual design, characteristics and performance figures of this implementation of AGATA at LNL.
Address (down) [Valiente-Dobon, J. J.; Goasduff, A.; Angelini, F.; Balogh, M.; Brugnara, D.; Cocconi, P.; Cogo, A.; Collado, J.; Ertoprak, A.; Galtarossa, F.; Gambalonga, A.; Gongora Servin, B.; Gottardo, A.; Gozzelino, A.; Gulmini, M.; Marchi, T.; Modanese, P.; Napoli, D. R.; Pellumaj, J.; Perez-Vidal, R. M.; Pilotto, E.; Raniero, W.; Rosso, D.; Scarpa, D.; Sedlak, M.; Toniolo, N.; Volpe, V.; Zago, L.; Zanon, I.; Allegrini, M. L.; Benini, D.; Biasotto, M.; Corradi, L.; De Angelis, G.; De Ruvo, L.; Fantinel, S.; Fioretto, E.; Minarello, A.; Stefanini, A. M.] INFN, Lab Nazl Legnaro, Legnaro, Italy, Email: valiente@lnl.infn.it
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:001020811800001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5590
Permanent link to this record
 
 
Author Valencia, E. et al; Tain, J.L.; Algora, A.; Agramunt, J.; Estevez, E.; Jordan, M.D.; Rubio, B.
Title Total absorption gamma-ray spectroscopy of the beta-delayed neutron emitters Br-87, Br-88, and Rb-94 Type Journal Article
Year 2017 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 95 Issue 2 Pages 024320 - 18pp
Keywords
Abstract We investigate the decay of Br-87,Br-88 and Rb-94 using total absorption gamma-ray spectroscopy. These important fission products are beta-delayed neutron emitters. Our data show considerable beta gamma intensity, so far unobserved in high-resolution gamma-ray spectroscopy, from states at high excitation energy. We also find significant differences with the beta intensity that can be deduced from existing measurements of the beta spectrum. We evaluate the impact of the present data on reactor decay heat using summation calculations. Although the effect is relatively small it helps to reduce the discrepancy between calculations and integral measurements of the photon component for U-235 fission at cooling times in the range 1-100 s. We also use summation calculations to evaluate the impact of present data on reactor antineutrino spectra. We find a significant effect at antineutrino energies in the range of 5 to 9 MeV. In addition, we observe an unexpected strong probability for. emission from neutron unbound states populated in the daughter nucleus. The. branching is compared to Hauser-Feshbach calculations, which allow one to explain the large value for bromine isotopes as due to nuclear structure. However the branching for Rb-94, although much smaller, hints of the need to increase the radiative width gamma by one order of magnitude. This increase in gamma would lead to a similar increase in the calculated (n, gamma) cross section for this very neutron-rich nucleus with a potential impact on r process abundance calculations.
Address (down) [Valencia, E.; Tain, J. L.; Algora, A.; Agramunt, J.; Estevez, E.; Jordan, M. D.; Rubio, B.] Univ Valencia, CSIC, Inst Fis Corpuscular, Apartado Correos 22085, E-46071 Valencia, Spain, Email: tain@ific.uv.es
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9985 ISBN Medium
Area Expedition Conference
Notes WOS:000394662200002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3015
Permanent link to this record