493 results on '"U. Garg"'
Search Results
2. Precise determination of quadrupole and hexadecapole deformation parameters of the sd-shell nucleus, 28Si
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Y.K. Gupta, V.B. Katariya, G.K. Prajapati, K. Hagino, D. Patel, V. Ranga, U. Garg, L.S. Danu, A. Pal, B.N. Joshi, S. Dubey, V.V. Desai, S. Panwar, N. Kumar, S. Mukhopadhyay, Pawan Singh, N. Sirswal, R. Sariyal, I. Mazumdar, and B.V. John
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Physics ,QC1-999 - Abstract
Quasi-elastic (QEL) scattering measurements have been performed using a 28Si projectile off a 90Zr target at energies around the Coulomb barrier. A Bayesian analysis within the framework of coupled channels (CC) calculations is performed in a large parameter space of quadrupole and hexadecapole deformations (β2 and β4) of 28Si. Our results unambiguously show that 28Si is an oblate shaped nucleus with β2=-0.38±0.01 which is in excellent agreement with results from electromagnetic probes. The sign and magnitude of quadrupole deformation along with a precise value of hexadecapole deformation (β4=+0.03±0.01) of 28Si have been determined for the first time using QEL scattering. A remarkable agreement is obtained between the experimental and calculated β4 values of 28Si based on Skyrme-Hartree-Fock method. The present results demonstrate the strong sensitivity of the quasi-elastic scattering to the sign and magnitude to the ground state deformation parameters, thus affirming its suitability to be used for rare exotic nuclei using low intensity RIBs.
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- 2023
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3. Corrigendum to 'Two-phonon wobbling in 135Pr' [Phys. Lett. B 792 (2019) 170–174]
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N. Sensharma, U. Garg, S. Zhu, A.D. Ayangeakaa, S. Frauendorf, W. Li, G.H. Bhat, J.A. Sheikh, M.P. Carpenter, Q.B. Chen, J.L. Cozzi, S.S. Ghugre, Y.K. Gupta, D.J. Hartley, K.B. Howard, R.V.F. Janssens, F.G. Kondev, T.C. McMaken, R. Palit, J. Sethi, D. Seweryniak, and R.P. Singh
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Physics ,QC1-999 - Published
- 2021
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4. Two-phonon wobbling in 135Pr
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N. Sensharma, U. Garg, S. Zhu, A.D. Ayangeakaa, S. Frauendorf, W. Li, G.H. Bhat, J.A. Sheikh, M.P. Carpenter, Q.B. Chen, J.L. Cozzi, S.S. Ghugre, Y.K. Gupta, D.J. Hartley, K.B. Howard, R.V.F. Janssens, F.G. Kondev, T.C. McMaken, R. Palit, J. Sethi, D. Seweryniak, and R.P. Singh
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Physics ,QC1-999 - Abstract
The second-phonon (nω=2) wobbling band has been established in the nucleus 135Pr. Conclusive evidence for its wobbling nature comes from the ΔI=1, E2 character of the transitions between the new band and the previously identified transverse wobbler band (nω=1) in this nucleus. Theoretical calculations in the framework of the quasiparticle triaxial rotor and triaxial projected shell models are found to be in good agreement with the experimental results.
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- 2019
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5. Compressional-mode resonances in the molybdenum isotopes: Emergence of softness in open-shell nuclei near A = 90
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K.B. Howard, U. Garg, M. Itoh, H. Akimune, M. Fujiwara, T. Furuno, Y.K. Gupta, M.N. Harakeh, K. Inaba, Y. Ishibashi, K. Karasudani, T. Kawabata, A. Kohda, Y. Matsuda, M. Murata, S. Nakamura, J. Okamoto, S. Ota, J. Piekarewicz, A. Sakaue, M. Şenyiğit, M. Tsumura, and Y. Yang
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Collectivity ,Giant resonance ,Nuclear incompressibility ,Softness ,Equation of state ,Physics ,QC1-999 - Abstract
“Why are the tin isotopes soft?” has remained, for the past decade, an open problem in nuclear structure physics: models which reproduce the isoscalar giant monopole resonance (ISGMR) in the “doubly-closed shell” nuclei, 90Zr and 208Pb, overestimate the ISGMR energies of the open-shell tin and cadmium nuclei, by as much as 1 MeV. In an effort to shed some light onto this problem, we present results of detailed studies of the ISGMR in the molybdenum nuclei, with the goal of elucidating where–and how–the softness manifests itself between 90Zr and the cadmium and tin isotopes. The experiment was conducted using the 94,96,98,100Mo(α,α′) reaction at Eα=386 MeV. A comparison of the results with relativistic, self-consistent Random-Phase Approximation calculations indicates that the ISGMR response begins to show softness in the molybdenum isotopes beginning with A=92.
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- 2020
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6. Determination of hexadecapole (β4) deformation of the light-mass nucleus 24Mg using quasi-elastic scattering measurements
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Y.K. Gupta, B.K. Nayak, U. Garg, K. Hagino, K.B. Howard, N. Sensharma, M. Şenyiğit, W.P. Tan, P.D. O'Malley, M. Smith, Ramandeep Gandhi, T. Anderson, R.J. deBoer, B. Frentz, A. Gyurjinyan, O. Hall, M.R. Hall, J. Hu, E. Lamere, Q. Liu, A. Long, W. Lu, S. Lyons, K. Ostdiek, C. Seymour, M. Skulski, and B. Vande Kolk
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Physics ,QC1-999 - Abstract
Quasi-elastic scattering measurements have been performed using 16O and 24Mg projectiles off 90Zr at energies around the Coulomb barrier. Experimental data have been analyzed in the framework of coupled channels (CC) calculations using the code CCFULL. The quasi-elastic scattering excitation function and derived barrier distribution for 16O + 90Zr reaction are well reproduced by the CC calculations using the vibrational coupling strengths for 90Zr reported in the literature. Using these vibrational coupling strengths, a Bayesian analysis is carried out for 24Mg + 90Zr reaction. The β2 and β4 values for 24Mg are determined to be +0.43±0.02 and −0.11±0.02, respectively. The β2 parameter determined in the present work is in good agreement with results obtained using inelastic scattering probes. The hexadecapole deformation of 24Mg has been measured very precisely for the first time. Present results establish that quasi-elastic scattering could provide a useful probe to determine the ground state deformation of atomic nuclei.
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- 2020
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7. Compression-mode resonances in the calcium isotopes and implications for the asymmetry term in nuclear incompressibility
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K.B. Howard, U. Garg, M. Itoh, H. Akimune, S. Bagchi, T. Doi, Y. Fujikawa, M. Fujiwara, T. Furuno, M.N. Harakeh, Y. Hijikata, K. Inaba, S. Ishida, N. Kalantar-Nayestanaki, T. Kawabata, S. Kawashima, K. Kitamura, N. Kobayashi, Y. Matsuda, A. Nakagawa, S. Nakamura, K. Nosaka, S. Okamoto, S. Ota, S. Weyhmiller, and Z. Yang
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Physics ,QC1-999 - Abstract
Recent data on isoscalar giant monopole resonance (ISGMR) in the calcium isotopes 40,44,48Ca have suggested that Kτ, the asymmetry term in the nuclear incompressibility, has a positive value. A value of Kτ>0 is entirely incompatible with present theoretical frameworks and, if correct, would have far-reaching implications on our understanding of myriad nuclear and astrophysical phenomena. This paper presents results of an independent ISGMR measurement with the 40,42,44,48Ca(α,α′) reaction at Eα=386 MeV. These results conclusively discount the possibility of a positive value for Kτ, and are consistent with the previously-obtained values for this quantity. Keywords: Collectivity, Giant resonance, Nuclear incompressibility, Equation of state
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- 2020
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8. Are there nuclear structure effects on the isoscalar giant monopole resonance and nuclear incompressibility near A∼90?
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Y.K. Gupta, U. Garg, K.B. Howard, J.T. Matta, M. Şenyiğit, M. Itoh, S. Ando, T. Aoki, A. Uchiyama, S. Adachi, M. Fujiwara, C. Iwamoto, A. Tamii, H. Akimune, C. Kadono, Y. Matsuda, T. Nakahara, T. Furuno, T. Kawabata, M. Tsumura, M.N. Harakeh, and N. Kalantar-Nayestanaki
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Physics ,QC1-999 - Abstract
“Background-free” spectra of inelastic α-particle scattering have been measured at a beam energy of 385 MeV in 90,92Zr and 92Mo at extremely forward angles, including 0°. The ISGMR strength distributions for the three nuclei coincide with each other, establishing clearly that nuclear incompressibility is not influenced by nuclear shell structure near A∼90 as was claimed in recent measurements.
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- 2016
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9. Observation of isoscalar multipole strengths in exotic doubly-magic 56Ni in inelastic α scattering in inverse kinematics
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S. Bagchi, J. Gibelin, M.N. Harakeh, N. Kalantar-Nayestanaki, N.L. Achouri, H. Akimune, B. Bastin, K. Boretzky, H. Bouzomita, M. Caamaño, L. Càceres, S. Damoy, F. Delaunay, B. Fernández-Domínguez, M. Fujiwara, U. Garg, G.F. Grinyer, O. Kamalou, E. Khan, A. Krasznahorkay, G. Lhoutellier, J.F. Libin, S. Lukyanov, K. Mazurek, M.A. Najafi, J. Pancin, Y. Penionzhkevich, L. Perrot, R. Raabe, C. Rigollet, T. Roger, S. Sambi, H. Savajols, M. Senoville, C. Stodel, L. Suen, J.C. Thomas, M. Vandebrouck, and J. Van de Walle
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Physics ,QC1-999 - Abstract
The Isoscalar Giant Monopole Resonance (ISGMR) and the Isoscalar Giant Dipole Resonance (ISGDR) compression modes have been studied in the doubly-magic unstable nucleus 56Ni. They were measured by inelastic α-particle scattering in inverse kinematics at 50 MeV/u with the MAYA active target at the GANIL facility. The centroid of the ISGMR has been obtained at Ex=19.1±0.5 MeV. Evidence for the low-lying part of the ISGDR has been found at Ex=17.4±0.7 MeV. The strength distribution for the dipole mode shows similarity with the prediction from the Hartree–Fock (HF) based random-phase approximation (RPA) [1]. These measurements confirm inelastic α-particle scattering as a suitable probe for exciting the ISGMR and the ISGDR modes in radioactive isotopes in inverse kinematics.
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- 2015
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10. Splitting of ISGMR strength in the light-mass nucleus 24Mg due to ground-state deformation
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Y.K. Gupta, U. Garg, J.T. Matta, D. Patel, T. Peach, J. Hoffman, K. Yoshida, M. Itoh, M. Fujiwara, K. Hara, H. Hashimoto, K. Nakanishi, M. Yosoi, H. Sakaguchi, S. Terashima, S. Kishi, T. Murakami, M. Uchida, Y. Yasuda, H. Akimune, T. Kawabata, and M.N. Harakeh
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Physics ,QC1-999 - Abstract
The isoscalar giant monopole resonance (ISGMR) strength distribution in 24Mg has been determined from background-free inelastic scattering of 386-MeV α particles at extreme forward angles, including 0∘. The ISGMR strength distribution has been observed for the first time to have a two-peak structure in a light-mass nucleus. This splitting of ISGMR strength is explained well by microscopic theory in terms of the prolate deformation of the ground state of 24Mg.
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- 2015
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11. Corrigendum to 'Splitting of ISGMR strength in the light-mass nucleus 24Mg due to ground-state deformation' [Phys. Lett. B 748 (2015) 343–346]
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Y.K. Gupta, U. Garg, J.T. Matta, D. Patel, T. Peach, J. Hoffman, K. Yoshida, M. Itoh, M. Fujiwara, K. Hara, H. Hashimoto, K. Nakanishi, M. Yosoi, H. Sakaguchi, S. Terashima, S. Kishi, T. Murakami, M. Uchida, Y. Yasuda, H. Akimune, T. Kawabata, and M.N. Harakeh
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Physics ,QC1-999 - Published
- 2015
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12. Evolution of structure and shapes in Er158 to ultrahigh spin
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J. Simpson, M. A. Riley, A. Pipidis, E. S. Paul, X. Wang, P. J. Nolan, J. F. Sharpey-Schafer, A. Aguilar, D. E. Appelbe, A. D. Ayangeakaa, A. J. Boston, H. C. Boston, D. B. Campbell, M. P. Carpenter, C. J. Chiara, P. T. W. Choy, R. M. Clark, M. Cromaz, A. O. Evans, P. Fallon, U. Garg, A. Görgen, D. J. Hartley, R. V. F. Janssens, D. T. Joss, D. S. Judson, F. G. Kondev, T. Lauritsen, I. Y. Lee, A. O. Macchiavelli, J. T. Matta, J. Ollier, M. Petri, J. P. Revill, L. L. Riedinger, S. V. Rigby, C. Teal, P. J. Twin, C. Unsworth, D. Ward, S. Zhu, and I. Ragnarsson
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- 2023
13. High Spin Study of 104Ag Nucleus
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Kaushik Katre, P. V. Madhusudhan Rao, K. Suryanarayana, A. Tejaswi, M. Kumar Raju, M.Ratna Raju, D. Vijayal Lakshmi, T. S. Reddy, J. Matta, A.D. Ayangeakaa, U. Garg, R. Raut, S.S. Ghugre, R. Palit, S. Chakraborty, S. Muralithar, and R.P. Singh
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High spin states in 104Ag were populated via heavy-ion (32S) induced fusion evaporation reaction at a beam energy of 110 MeV. The de-exciting γ-rays were detected by 18 Compton suppressed HPGe clover detectors, placed in different (θ, φ) angles. Spin of several excited states were assigned firmly from the present angular correlation measurement.
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- 2022
14. Single-particle configurations of the excited states of Po203
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S. Chatterjee, B. Mondal, A. Ghosh, D. Arora, S. Das, S. Samanta, R. Raut, S. S. Ghugre, P. C. Srivastava, A. K. Sinha, U. Garg, H. K. Singh, null Neelam, K. Rojeeta Devi, A. Sharma, S. S. Bhattacharjee, R. Garg, I. Bala, R. P. Singh, and S. Muralithar
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FOS: Physical sciences ,Nuclear Experiment (nucl-ex) ,Nuclear Experiment - Abstract
Excited states of the $^{203}$Po ($Z = 84, N = 119$) have been investigated after populating them through $^{194}$Pt($^{13}$C,4n) fusion-evaporation reaction at E$_{beam}$ = 74 MeV and using a large array of Compton suppressed HPGe clover detectors as the detection setup for the emitted $\gamma$-rays. Standard techniques of $\gamma$-ray spectroscopy have been applied towards establishing the level structure of the nucleus. Twenty new $\gamma$-ray transitions have been identified therein, through $\gamma-\gamma$ coincidence measurements, and spin-parity assignments of several states have been determined or confirmed, following the angular correlation and linear polarization measurements on the observed $\gamma$-rays. The excited states have been interpreted in the framework of large basis shell model calculations, while comparing their calculated and experimental energies. They have been principally ascribed to proton population in the $h_{9/2}$ and $i_{13/2}$ orbitals outside the $Z = 82$ closure and neutron occupation of the $f_{5/2}$, $p_{3/2}$ and $i_{13/2}$ orbitals in the $N = 126$ shell.
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- 2022
15. Chiral-like doublet band structure and octupole correlations in Ag104
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Kaushik Katre, P. V. Madhusudhana Rao, R. Raut, A. Sharma, K. Suryanarayana, A. Tejaswi, M. Ratna Raju, D. Vijaya Lakshmi, T. Seshi Reddy, M. Kumar Raju, S. Jehangir, N. Rather, G. H. Bhat, Nazira Nazir, J. A. Sheikh, Y. P. Wang, J. T. Matta, A. D. Ayangeakaa, U. Garg, S. S. Ghugre, T. Trivedi, B. S. Naidu, R. Palit, S. Saha, S. Muralithar, and R. P. Singh
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- 2022
16. Experimental investigation of high-spin states in Zr90
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P. Dey, D. Negi, R. Palit, P. C. Srivastava, Md. S. R. Laskar, B. Das, F. S. Babra, S. Bhattacharya, Biswajit Das, K. Rojeeta Devi, R. Gala, U. Garg, S. S. Ghugre, E. Ideguchi, S. Kumar, A. Kundu, G. Mukherjee, S. Muralithar, S. Nag, S. Nandi, null Neelam, M. Kumar Raja, R. Raut, R. Santra, A. Sharma, S. Sihotra, A. K. Singh, R. P. Singh, and T. Trivedi
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- 2022
17. Erratum: Transverse Wobbling in Pr135 [Phys. Rev. Lett. 114 , 082501 (2015)]
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S. Zhu, R. Palit, R. V. F. Janssens, A. D. Ayangeakaa, J. T. Matta, U. Garg, M. P. Carpenter, and S. S. Ghugre
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Physics ,Transverse plane ,Condensed matter physics ,General Physics and Astronomy - Published
- 2021
18. Enhanced B(E3) strength observed in La137
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S. C. Pancholi, F. S. Babra, Eiji Ideguchi, Ashok Kumar Jain, D. Kumar, Anirban Kundu, Banamali Das, R. Palit, Tsunenori Inakura, S. N. Mishra, S. Rajbanshi, U. Garg, D. Negi, S K Bhattacharya, D. Choudhury, S. Sihotra, Md. S. R. Laskar, Biswajit Das, and P. Dey
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Physics ,Proton ,Transition density ,Atomic physics ,Beam energy - Abstract
The $^{137}\mathrm{La}$ nucleus was populated by the reaction $^{130}\mathrm{Te}(^{11}\mathrm{B}, 4n$) at 40-MeV beam energy and the lifetime of the $11/{2}^{\ensuremath{-}}$ state at $1004.6\phantom{\rule{0.28em}{0ex}}\mathrm{keV}$ was measured using a hybrid array of HPGe clover and ${\mathrm{LaBr}}_{3}$(Ce) detectors by electronic fast-timing technique, providing the value ${T}_{1/2}=263\ifmmode\pm\else\textpm\fi{}12\phantom{\rule{0.28em}{0ex}}\mathrm{ps}$. The reduced transition probability $B(E3)=23.3\ifmmode\pm\else\textpm\fi{}2.4\phantom{\rule{0.28em}{0ex}}\mathrm{W}.\mathrm{u}.$ is found to be significantly larger compared to the values observed in lighter odd-$A$ La isotopes. The experimentally determined $B(E3)$ value is compared with theoretical calculations of random-phase approximation which explains the enhanced transition probability to be arising from higher contribution of the ${g}_{9/2}$ orbital to the proton transition density.
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- 2021
19. Investigation of the isoscalar response of Mg24 to Li6 scattering
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Shumpei Noji, G. Gey, Y. Yamamoto, L. Batail, S. Zhu, R. Titus, Eiji Ideguchi, P. von Neumann-Cosel, A. Inoue, J. C. Zamora, Hooi Jin Ong, J. Schmitt, Johann Isaak, M. P. Carpenter, Nori Aoi, T. H. Hoang, U. Garg, J. J. Carroll, V. Werner, X. K. Zhou, M. L. Liu, Takeshi Koike, Nobuyuki Kobayashi, C. Kacir, C. J. Guess, D. Bazin, Hisanori Fujita, R. G. T. Zegers, Chihiro Iwamoto, Sophie Péru, N. Ichige, C. Sullivan, Atsushi Tamii, S. Lipschutz, E. Hudson, J. Pereira, M.N. Harakeh, M. Kumar Raju, and Y. D. Fang
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Physics ,010308 nuclear & particles physics ,Scattering ,Isoscalar ,Nuclear Theory ,Resonance ,Inelastic scattering ,01 natural sciences ,Molecular physics ,0103 physical sciences ,Quadrupole ,010306 general physics ,Random phase approximation ,Ground state ,Multipole expansion - Abstract
Background: Mg 24 is a strongly deformed nucleus in the ground state. Deformation effects can be observed in the structure of the isoscalar giant monopole and quadrupole resonances. Mg 24 is also a nucleus that is well known to present different types of cluster-oscillation modes. Both giant resonances and cluster states are strongly populated by isoscalar transitions. Purpose: To extract the E 0 , E 1 , and E 2 transition strengths via Li 6 scattering. The Li 6 probe is a powerful tool for investigating the isoscalar nuclear response with a very favorable ratio of resonance-to-continuum background. Method: Double-differential cross sections of Li 6 inelastic scattering, at the beam energy of 100 MeV/u, were measured in the excitation-energy range 10 – 40 MeV and scattering angles 0 − 3 ∘ . A multipole-decomposition analysis was performed for extracting the isoscalar E 0 , E 1 , and E 2 strength distributions. Results: The extracted multipole strengths were compared with predictions from consistent quasiparticle random phase approximation calculations. The theoretical predictions are in fair agreement with the experimental data. The E 0 strength was also compared with results from antisymmetrized molecular dynamics calculations found in the literature. A few peaks in the experimental data might be associated with clustering in Mg 24 . Conclusions: Ground-state deformation effects were observed in the isoscalar giant monopole resonance (ISGMR) and isoscalar giant quadrupole resonance (ISGQR) distributions. The ISGMR strength is split in two peaks around 19 and 28 MeV. The ISGQR exhibits a pronounced peak at 20 MeV with a broadening at the low-energy region, similar to predictions from microscopic calculations. Signatures of excitation of cluster states were observed in the E 0 response. Further studies including particle-decay measurements will be required to confirm the nature of the observed peaks.
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- 2021
20. Two-phonon wobbling in 135Pr
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Q. B. Chen, N. Sensharma, A. D. Ayangeakaa, Y. K. Gupta, D. Seweryniak, J. L. Cozzi, J. Sethi, R. V. F. Janssens, F. G. Kondev, G. H. Bhat, S. S. Ghugre, D. J. Hartley, M. P. Carpenter, S. Zhu, J. A. Sheikh, R. P. Singh, S. Frauendorf, K. B. Howard, R. Palit, Wei Li, T. C. McMaken, and U. Garg
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Physics ,Nuclear and High Energy Physics ,Condensed matter physics ,010308 nuclear & particles physics ,Rotor (electric) ,Phonon ,Shell (structure) ,Conclusive evidence ,01 natural sciences ,lcsh:QC1-999 ,law.invention ,Transverse plane ,medicine.anatomical_structure ,Character (mathematics) ,law ,0103 physical sciences ,Quasiparticle ,medicine ,010306 general physics ,Nucleus ,lcsh:Physics - Abstract
The second-phonon ( n ω = 2 ) wobbling band has been established in the nucleus 135Pr. Conclusive evidence for its wobbling nature comes from the Δ I = 1 , E2 character of the transitions between the new band and the previously identified transverse wobbler band ( n ω = 1 ) in this nucleus. Theoretical calculations in the framework of the quasiparticle triaxial rotor and triaxial projected shell models are found to be in good agreement with the experimental results.
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- 2019
21. Evidence of antimagnetic rotational motion in Pd103
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R. Palit, A. Sharma, S. Samanta, R. P. Singh, S. Muralithar, P. V. Madhusudhana Rao, S. S. Bhattacharjee, S. S. Tiwary, G. H. Bhat, S. S. Ghugre, R. Raut, J. A. Sheikh, Shashi K. Dhiman, N. Rather, S. Jehangir, Neelam, S. Das, and U. Garg
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Physics ,Valence (chemistry) ,010308 nuclear & particles physics ,Yrast ,Rotation around a fixed axis ,Parity (physics) ,01 natural sciences ,0103 physical sciences ,Density functional theory ,Atomic physics ,010306 general physics ,Nucleon ,Electronic band structure ,Spin-½ - Abstract
Lifetime measurements have been carried out for the levels of the negative parity yrast sequence in $^{103}\mathrm{Pd}$ nucleus using the Doppler shift attenuation method. The levels were populated via $^{94}\mathrm{Zr}(^{13}\mathrm{C}, 4n\ensuremath{\gamma})^{103}\mathrm{Pd}$ fusion-evaporation reaction at a beam energy of 55 MeV. De-exciting $\ensuremath{\gamma}$ rays were detected by utilizing the Indian National Gamma Array. The extracted transition probabilities and other auxiliary observations indicate that the sequence may be resulting from the antimagnetic rotational (AMR) motion of valence nucleons. The key characteristic feature of the AMR motion is the steady decrease of the $B(E2)$ transition probability with spin, which is seen in the present measured transitions for $^{103}\mathrm{Pd}$. The experimental results are compared with the theoretical predictions of tilted axis cranked approach based on the covariant density functional theory. It is noted that the properties of the AMR band structure for $^{103}\mathrm{Pd}$ predicted in this model analysis are in good agreement with the present experimental findings. Further, semi-classical particle-rotor model has been employed to substantiate the AMR interpretation of the observed band structure in $^{103}\mathrm{Pd}$ and it is shown that results are similar to the band structures observed in the neighboring isotopes, which have also been considered as candidates for AMR motion.
- Published
- 2021
22. Investigation of the alignment mechanism and loss of collectivity in Pm135
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S. Saha, U. Garg, Banamali Das, L. P. Singh, G. H. Bhat, R. Palit, P. Singh, J. A. Sheikh, Md. S. R. Laskar, C. S. Palshetkar, S. Jehangir, P. Dey, S. Rajbanshi, S. Biswas, F. S. Babra, and Biswajit Das
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Physics ,010308 nuclear & particles physics ,Yrast ,Nuclear Theory ,SHELL model ,01 natural sciences ,Excited state ,0103 physical sciences ,Atomic physics ,Nuclear Experiment ,010306 general physics ,Beam energy ,Excitation ,Spin-½ - Abstract
High-spin excited states of $^{135}\mathrm{Pm}$ have been investigated using the $^{107}\mathrm{Ag}(^{32}\mathrm{S}$, $2p2n$) reaction at 145-MeV beam energy. Three negative-parity bands have been investigated up to $\ensuremath{\sim}9.0\ensuremath{-}$, $7.6\ensuremath{-}$, and $6.9\ensuremath{-}\mathrm{MeV}$ excitation energies with spin parities $(55/{2}^{\ensuremath{-}})$, $(49/{2}^{\ensuremath{-}})$, and $(47/{2}^{\ensuremath{-}})\phantom{\rule{4pt}{0ex}}\ensuremath{\hbar}$, respectively. The experimental results have been interpreted using the triaxial projected shell model. It is shown that the observation of the parallel band structures can be explained in terms of crossing of two $s$ bands with the yrast band, which is a rare phenomenon for an odd-$A$ nucleus. Further, the lifetimes of levels in yrast band have been extracted using Doppler shift attenuation method. The evaluated $B(E2)$ values of yrast states show the loss of collectivity at higher spin, attributed to the alignment process.
- Published
- 2021
23. Signature of a possible $\alpha $-cluster state in $N=Z$ doubly-magic $^{56}$Ni
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L. Perrot, S. M. Lukyanov, U. Garg, L. Caceres, B. Bastin, A. Krasznahorkay, M. A. Najafi, J. F. Libin, S. Damoy, Marine Vandebrouck, Franck Delaunay, Catherine Rigollet, L. Suen, M. Caamaño, Julien Gibelin, K. Boretzky, J. Van de Walle, Nasser Kalantar-Nayestanaki, Hidetoshi Akimune, H. Bouzomita, G. Lhoutellier, C. Stodel, J. Pancin, Riccardo Raabe, S. Bagchi, O. Kamalou, H. Savajols, M.N. Harakeh, T. Roger, B. Fernández-Domínguez, Y. E. Penionzhkevich, M. Sénoville, N. L. Achouri, K. Mazurek, G. F. Grinyer, E. Khan, S. Sambi, J. C. Thomas, M. Fujiwara, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)
- Subjects
Nuclear and High Energy Physics ,Hadron ,[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] ,01 natural sciences ,Physics, Particles & Fields ,0103 physical sciences ,medicine ,Incident energy ,Nuclear fusion ,ddc:530 ,Multiplicity (chemistry) ,Nuclear Experiment ,010306 general physics ,ComputingMilieux_MISCELLANEOUS ,Physics ,Science & Technology ,010308 nuclear & particles physics ,Cluster state ,Physics, Nuclear ,medicine.anatomical_structure ,Physical Sciences ,Atomic physics ,α particles ,Nucleus ,Excitation - Abstract
An inelastic $\alpha$-scattering experiment on the unstable $N=Z$, doubly-magic $^{56}$Ni nucleus was performed in inverse kinematics at an incident energy of 50 A.MeV at GANIL. High multiplicity for $\alpha$-particle emission was observed within the limited phase-space of the experimental setup. This observation cannot be explained by means of the statistical-decay model. The ideal classical gas model at $kT$ = 0.4 MeV reproduces fairly well the experimental momentum distribution and the observed multiplicity of $\alpha$ particles corresponds to an excitation energy around 96 MeV. The method of distributed $m\alpha$-decay ensembles is in agreement with the experimental results if we assume that the $\alpha$-gas state in $^{56}$Ni exists at around $113^{+15}_{-17}$ MeV. These results suggest that there may exist an exotic state consisting of many $\alpha$ particles at the excitation energy of $113^{+15}_{-17}$ MeV., Comment: Accepted for publication in the European Physical Journal A
- Published
- 2020
24. Determination of hexadecapole (β4) deformation of the light-mass nucleus 24Mg using quasi-elastic scattering measurements
- Author
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Stephanie Lyons, Patrick O'Malley, U. Garg, J. Hu, Christopher Seymour, Wanpeng Tan, M. Şenyiğit, A. Gyurjinyan, T. Anderson, Y. K. Gupta, M. R. Hall, B. K. Nayak, Q. Liu, B. Vande Kolk, B. Frentz, N. Sensharma, Kouichi Hagino, Wenting Lu, Richard deBoer, Karen Ostdiek, O. Hall, K. B. Howard, Michael S. Smith, Edward Lamere, Ramandeep Gandhi, Michael Skulski, and A. Long
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Excitation function ,Physics ,Elastic scattering ,Nuclear and High Energy Physics ,010308 nuclear & particles physics ,Scattering ,Coulomb barrier ,Inelastic scattering ,01 natural sciences ,Molecular physics ,lcsh:QC1-999 ,0103 physical sciences ,Atomic nucleus ,010306 general physics ,Ground state ,Rotational–vibrational coupling ,lcsh:Physics - Abstract
Quasi-elastic scattering measurements have been performed using 16O and 24Mg projectiles off 90Zr at energies around the Coulomb barrier. Experimental data have been analyzed in the framework of coupled channels (CC) calculations using the code CCFULL. The quasi-elastic scattering excitation function and derived barrier distribution for 16O + 90Zr reaction are well reproduced by the CC calculations using the vibrational coupling strengths for 90Zr reported in the literature. Using these vibrational coupling strengths, a Bayesian analysis is carried out for 24Mg + 90Zr reaction. The β 2 and β 4 values for 24Mg are determined to be + 0.43 ± 0.02 and − 0.11 ± 0.02 , respectively. The β 2 parameter determined in the present work is in good agreement with results obtained using inelastic scattering probes. The hexadecapole deformation of 24Mg has been measured very precisely for the first time. Present results establish that quasi-elastic scattering could provide a useful probe to determine the ground state deformation of atomic nuclei.
- Published
- 2020
25. Reexamination of isoscalar giant resonances in C12 and Nb93 through Li6 scattering
- Author
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J. C. Zamora, J. Schmitt, C. J. Guess, V. Werner, Shumpei Noji, G. Gey, Nobuyuki Kobayashi, Y. Yamamoto, S. Zhu, T. H. Hoang, I. Deloncle, L. Batail, R. Titus, D. Bazin, S. Péru, R. G. T. Zegers, X. K. Zhou, J. Pereira, E. Hudson, C. Kacir, U. Garg, Takeshi Koike, C. Sullivan, M. P. Carpenter, Atsushi Tamii, Nori Aoi, S. Lipschutz, Eiji Ideguchi, Hisanori Fujita, Hooi Jin Ong, M.N. Harakeh, A. Inoue, Johann Isaak, Chihiro Iwamoto, M. L. Liu, Y. D. Fang, J. J. Carroll, M. Kumar Raju, N. Ichige, and P. von Neumann-Cosel
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Mass number ,Physics ,010308 nuclear & particles physics ,Scattering ,Isoscalar ,Magnetic monopole ,Nuclear structure ,Resonance ,01 natural sciences ,Excited state ,0103 physical sciences ,Sum rule in quantum mechanics ,Atomic physics ,Nuclear Experiment ,010306 general physics - Abstract
Inelastic ${}^{6}$Li scattering at 100 MeV/u on ${}^{12}$C and ${}^{93}$Nb have been measured with the high-resolution magnetic spectrometer Grand Raiden. The magnetic-rigidity settings of the spectrometer covered excitation energies from 10 to 40 MeV and scattering angles in the range $0^\circ < \theta_{\text{lab.}}< 2^\circ$. The isoscalar giant monopole resonance was selectively excited in the present data. Measurements free of instrumental background and the very favorable resonance-to-continuum ratio of ${}^{6}$Li scattering allowed for precise determination of the $E0$ strengths in ${}^{12}$C and ${}^{93}$Nb. It was found that the monopole strength in ${}^{12}$C exhausts $52 \pm 3^\text{(stat.)} \pm 8 ^\text{(sys.)}$\% of the energy-weighted sum rule (EWSR), which is considerably higher than results from previous $\alpha$-scattering experiments. The monopole strength in ${}^{93}$Nb exhausts $92 \pm 4^\text{(stat.)} \pm 10 ^\text{(sys.)}$\% of the EWSR, and it is consistent with measurements of nuclei with mass number of $A\approx90$. Such comparison indicates that the isoscalar giant monopole resonance distributions in these nuclei are very similar, and no influence due to nuclear structure was observed.
- Published
- 2020
26. Structure of the 11/2− isomeric state in La133
- Author
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Md. S. R. Laskar, Z. Naik, S. N. Mishra, Noritaka Shimizu, U. Garg, S. Biswas, R. Gala, R. Palit, F. S. Babra, Eiji Ideguchi, C. S. Palshetkar, and Yutaka Utsuno
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Physics ,010308 nuclear & particles physics ,SHELL model ,Structure (category theory) ,State (functional analysis) ,01 natural sciences ,Angular distribution ,0103 physical sciences ,Quadrupole ,Atomic physics ,010306 general physics ,Hyperfine structure ,Magnetic dipole ,Beam energy - Abstract
We report measurement of the $g$-factor for the ${11/2}^{\ensuremath{-}}$ isomeric state at 535 keV in $^{133}\mathrm{La}$, employing the time differential perturbed angular distribution technique (TDPAD). This isomer was populated in the reaction $^{126}\mathrm{Te}(^{11}\mathrm{B}$, $4n)^{133}\mathrm{La}$ at beam energy of 52 MeV. From the observed nuclear spin precession, analysed through combined, magnetic dipole and electric quadrupole hyperfine interactions, we obtain the $g$ factor for the $11/{2}^{\ensuremath{-}}$ state as $g=1.16\ifmmode\pm\else\textpm\fi{}0.07$. In addition, this analysis provides the spectroscopic quadrupole moment $|Q|=1.71\ifmmode\pm\else\textpm\fi{}0.34\phantom{\rule{3.33333pt}{0ex}}b$, yielding the deformation parameter $\ensuremath{\beta}=0.28\ifmmode\pm\else\textpm\fi{}0.10$. Further, we have performed theoretical calculations using the large-scale shell model and the Monte Carlo shell model. The results successfully describe the low-lying levels and the band structures of $^{133}\mathrm{La}$, and the calculated $g$ factor compares well with the values obtained from our experiment. The dominant configuration of $11/{2}^{\ensuremath{-}}$ isomeric state in $^{133}\mathrm{La}$ is inferred to be $\ensuremath{\pi}({h}_{11/2})\ensuremath{\bigotimes}^{132}\mathrm{Ba}({0}^{+})$.
- Published
- 2020
27. Fragmentation of Single-Particle Strength around the Doubly Magic Nucleus Sn132 and the Position of the 0f5/2 Proton-Hole State in In131
- Author
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Hiroyoshi Sakurai, J. Tscheuschner, Yosuke Kondo, A. Bracco, D. Semmler, S. Nishimura, T. Motobayashi, Ryo Taniuchi, N. Imai, Kazuo Ieki, A. Jungclaus, Ismael Martel, F. Camera, P. Schrock, Heiko Scheit, Juzo Zenihiro, Andreas Zilges, V. Derya, D. S. Ahn, K. Boretzky, Yasuhiro Togano, R. Avigo, M.N. Harakeh, D. Symochko, Hiroyuki Takeda, T. Kubo, Shoko Koyama, D. M. Rossi, M. Shikata, H. Baba, Agnese Giaz, Haik Simon, T. Ozaki, J. L. Rodriguez-Sanchez, P. Doornenbal, David Steppenbeck, Atsumi Saito, I. Syndikus, C. Caesar, M. Heil, Si-Ge Chen, J. A. Tostevin, J. Tsubota, Nagao Kobayashi, Deniz Savran, Yoshiaki Shiga, U. Garg, Marina Petri, N. Nakatsuka, Masafumi Matsushita, Toshiyuki Sumikama, Naohito Inabe, Victor Vaquero, Takashi Nakamura, B. Million, J. Endres, Satoshi Takeuchi, A. Horvat, Y. Shimizu, E. V. Litvinova, K. Yoneda, H. Suzuki, O. Wieland, Rene Reifarth, Hideaki Otsu, H. Wang, Fabia Schindler, Shuichi Ota, Nasser Kalantar-Nayestanaki, M. Nishimura, Thomas Aumann, and N. Fukuda
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Physics ,medicine.anatomical_structure ,Fragmentation (mass spectrometry) ,Astrophysics::High Energy Astrophysical Phenomena ,Excited state ,0103 physical sciences ,Magic (programming) ,medicine ,General Physics and Astronomy ,Atomic physics ,010306 general physics ,01 natural sciences ,Nucleus - Abstract
Spectroscopic factors of neutron-hole and proton-hole states in 131Sn and 131In, respectively, were measured using one-nucleon removal reactions from doubly magic 132Sn at relativistic energies. For 131In, a 2910(50)-keV γ ray was observed for the first time and tentatively assigned to a decay from a 5=2− state at 3275(50) keV to the known 1=2− level at 365 keV. The spectroscopic factors determined for this new excited state and three other single-hole states provide first evidence for a strong fragmentation of singlehole strength in 131Sn and 131In. The experimental results are compared to theoretical calculations based on the relativistic particle-vibration coupling
- Published
- 2020
28. Where we stand on structure dependence of ISGMR in the Zr-Mo region
- Author
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Y. K. Gupta, K. B. Howard, Mohsen Harakeh, U. Garg, and Research unit Nuclear & Hadron Physics
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Physics ,Nuclear and High Energy Physics ,Equation of state ,Nuclear Theory ,Field (physics) ,010308 nuclear & particles physics ,GIANT MONOPOLE RESONANCE ,Isoscalar ,Magnetic monopole ,FOS: Physical sciences ,Resonance ,Context (language use) ,01 natural sciences ,Nuclear Theory (nucl-th) ,Nuclear physics ,SUM-RULES ,0103 physical sciences ,STRENGTH ,Nuclear fusion ,Sum rule in quantum mechanics ,Nuclear Experiment (nucl-ex) ,010306 general physics ,Nuclear Experiment - Abstract
Isoscalar giant resonances, being the archetypal forms of collective nuclear behavior, have been studied extensively for decades with the goal of constraining bulk nuclear properties of the equation of state, as well as for modeling dynamical behaviors within stellar environments. An important such mode is the isoscalar electric giant monopole resonance (ISGMR) that can be understood as a radially symmetric density vibration within the saturated nuclear volume. The field has a few key open questions, which have been proposed and remain unresolved. One of the more provocative questions is the extra high-energy strength in the $A\approx 90$ region, which manifested in large percentages of the $E0$ sum rule in $^{92}$Zr and $^{92}$Mo above the main ISGMR peak. The purpose of this article is to introduce these questions within the context of experimental investigations into the phenomena in the zirconium and molybdenum isotopic chains, and to address, via a discussion of previously published and preliminary results, the implications of recent experimental efforts on extraction of the nuclear incompressibility from this data., 9 pages, 7 figures, invited to be submitted to a special issue of EPJA honoring Prof. P. F. Bortignon
- Published
- 2019
29. Corrigendum to 'Two-phonon wobbling in 135Pr' [Phys. Lett. B 792 (2019) 170–174]
- Author
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Y. K. Gupta, Q. B. Chen, D. Seweryniak, Wei Li, U. Garg, M. P. Carpenter, R. V. F. Janssens, R. Palit, J. Sethi, T. C. McMaken, S. Frauendorf, G. H. Bhat, N. Sensharma, D. J. Hartley, J. A. Sheikh, F. G. Kondev, K. B. Howard, R. P. Singh, J. L. Cozzi, A. D. Ayangeakaa, S. S. Ghugre, and S. Zhu
- Subjects
Physics ,Nuclear and High Energy Physics ,Condensed matter physics ,Phonon ,QC1-999 - Published
- 2021
30. Fragmentation of Single-Particle Strength around the Doubly Magic Nucleus ^{132}Sn and the Position of the 0f_{5/2} Proton-Hole State in ^{131}In
- Author
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V, Vaquero, A, Jungclaus, T, Aumann, J, Tscheuschner, E V, Litvinova, J A, Tostevin, H, Baba, D S, Ahn, R, Avigo, K, Boretzky, A, Bracco, C, Caesar, F, Camera, S, Chen, V, Derya, P, Doornenbal, J, Endres, N, Fukuda, U, Garg, A, Giaz, M N, Harakeh, M, Heil, A, Horvat, K, Ieki, N, Imai, N, Inabe, N, Kalantar-Nayestanaki, N, Kobayashi, Y, Kondo, S, Koyama, T, Kubo, I, Martel, M, Matsushita, B, Million, T, Motobayashi, T, Nakamura, N, Nakatsuka, M, Nishimura, S, Nishimura, S, Ota, H, Otsu, T, Ozaki, M, Petri, R, Reifarth, J L, Rodríguez-Sánchez, D, Rossi, A T, Saito, H, Sakurai, D, Savran, H, Scheit, F, Schindler, P, Schrock, D, Semmler, Y, Shiga, M, Shikata, Y, Shimizu, H, Simon, D, Steppenbeck, H, Suzuki, T, Sumikama, D, Symochko, I, Syndikus, H, Takeda, S, Takeuchi, R, Taniuchi, Y, Togano, J, Tsubota, H, Wang, O, Wieland, K, Yoneda, J, Zenihiro, and A, Zilges
- Abstract
Spectroscopic factors of neutron-hole and proton-hole states in ^{131}Sn and ^{131}In, respectively, were measured using one-nucleon removal reactions from doubly magic ^{132}Sn at relativistic energies. For ^{131}In, a 2910(50)-keV γ ray was observed for the first time and tentatively assigned to a decay from a 5/2^{-} state at 3275(50) keV to the known 1/2^{-} level at 365 keV. The spectroscopic factors determined for this new excited state and three other single-hole states provide first evidence for a strong fragmentation of single-hole strength in ^{131}Sn and ^{131}In. The experimental results are compared to theoretical calculations based on the relativistic particle-vibration coupling model and to experimental information for single-hole states in the stable doubly magic nucleus ^{208}Pb.
- Published
- 2019
31. Investigation of a large change in deformation for the γ -soft nucleus Sm136
- Author
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P. Singh, U. Garg, S. Saha, S. Biswas, R. Palit, Md. S. R. Laskar, Biswajit Das, S. Jehangir, S. Rajbanshi, J. Sethi, G. H. Bhat, C. S. Palshetkar, J. A. Sheikh, and F. S. Babra
- Subjects
Physics ,010308 nuclear & particles physics ,Nuclear Theory ,SHELL model ,Prolate spheroid ,01 natural sciences ,medicine.anatomical_structure ,Excited state ,0103 physical sciences ,Quadrupole ,medicine ,Atomic physics ,Deformation (engineering) ,010306 general physics ,Spin (physics) ,Beam energy ,Nucleus - Abstract
Lifetimes of excited states of the ground-state rotational band in the $^{136}\mathrm{Sm}$ nucleus have been measured up to ${I}^{\ensuremath{\pi}}={20}^{+}$ using the Doppler-shift attenuation method. The states were populated in the reaction $^{107}\mathrm{Ag}$($^{32}\mathrm{S}$, $1p2n$) at 145-MeV beam energy and the $\ensuremath{\gamma}$ rays emitted from the excited states were detected using the Indian National Gamma Array at the Tata Institute of Fundamental Research, Mumbai. The extracted transitional quadrupole moments indicate a reduction of collectivity with increasing spin after the band crossing. The results have been compared with the predictions of the cranked shell model as well as the triaxial projected shell-model calculations and indicate that the nucleus evolves from prolate $\ensuremath{\gamma}$-soft to a stable triaxially deformed shape after the first and the second crossing involving $\ensuremath{\pi}{h}_{11/2}^{2}$ and $\ensuremath{\pi}{h}_{11/2}^{2}\ensuremath{\bigotimes}\ensuremath{\nu}{h}_{11/2}^{2}$ configurations, respectively.
- Published
- 2019
32. Backbending, seniority, and Pauli blocking of pairing correlations at high rotational frequencies in rapidly rotating nuclei
- Author
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S. Zhu, E. A. McCutchan, M. P. Carpenter, P. F. Bertone, T. Lauritsen, Alexander Volya, J. Cavey, P. Chowdhury, J. T. Matta, J.F. Sharpey-Schafer, E.G. Jackson, K. Villafana, J. J. Carroll, F. G. Kondev, C. J. Chiara, S. S. Hota, A. D. Ayangeakaa, A. J. Boston, D. J. Hartley, Jayne Simpson, Xuan Wang, Saul L. Miller, S. Mukhopadhyay, R. V. F. Janssens, E. S. Paul, M. A. Riley, Jill S. Baron, U. Garg, Marc Litz, W. C. Ma, J. R. Vanhoy, P. J. Nolan, E. E. Pedicini, and L. L. Riedinger
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Physics ,symbols.namesake ,Pauli exclusion principle ,Blocking (radio) ,Quantum mechanics ,Pairing ,symbols ,Seniority - Abstract
Garrett et al. systematically investigated band-crossing frequencies resulting from the rotational alignment of the first pair of i13/2 neutrons (AB) in rare-earth nuclei. In that study, evidence was found for an odd-even neutron number dependence attributed to changes in the strength of neutron pairing correlations. The present paper carries out a similar investigation at higher rotational frequencies for the second pair of aligning i13/2 neutrons (BC). Again, a systematic difference in band-crossing frequencies is observed between odd-N and even-N Er, Yb, Hf, and W nuclei, but in the BC case, it is opposite to the AB neutron-number dependence. These results are discussed in terms of a reduction of neutron pairing correlations at high rotational frequencies and of the effects of Pauli blocking on the pairing field by higher-seniority configurations. Also playing a significant role are the changes in deformation with proton and neutron numbers, the changes in location of single-particle orbitals as a function of quadrupole deformation, and the position of the Fermi surface with regard to the various ω components of the neutron i13/2 shell.
- Published
- 2019
33. Observation of rotation about the longest principal axis in Zr89
- Author
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R. Palit, Shaji Kumar, F. S. Babra, S. Saha, Amrendra K. Singh, J. Sethi, Purnima Singh, Sanjoy Biswas, H. C. Jain, Anindya Goswami, Md. S. R. Laskar, G. Mukherjee, Z. Naik, Sudip Nag, Eiji Ideguchi, C. S. Palshetkar, Ingemar Ragnarsson, and U. Garg
- Subjects
Physics ,Spins ,010308 nuclear & particles physics ,Nuclear Theory ,Nuclear structure ,Parity (physics) ,Polarization (waves) ,01 natural sciences ,Dipole ,medicine.anatomical_structure ,0103 physical sciences ,medicine ,Atomic physics ,010306 general physics ,Nucleus ,Principal axis theorem - Abstract
High-spin states in Zr89 were populated in the Se80(C13,4n) reaction, and γ-ray coincidences were measured using the Indian National Gamma Array. The level scheme of Zr89 has been extended up to spin I=49/2 with the observation of a new dipole band. Directional correlation and polarization asymmetries of the γ rays have been measured to determine spin and parity of the levels. Line shapes of several transitions have been analyzed to determine lifetimes of the levels. Possible configurations of the band have been discussed using the cranked Nilsson-Strutinsky model. The calculations suggest a triaxial shape of the nucleus at high spins, and the band may represent rotation of the nucleus about the longest axis.
- Published
- 2019
34. Single particle configurations in Ni61
- Author
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Ratnajit Bhattacharjee, F. S. Babra, S. S. Ghugre, A. K. Sinha, Neelam, Md. S. R. Laskar, Purnima Singh, R. Palit, Subhasis Samanta, S. K. Das, Sandeep Chatterjee, U. Garg, P. Jones, S. Saha, R. Raut, S. Biswas, and N. Kumar
- Subjects
Physics ,010308 nuclear & particles physics ,chemistry.chemical_element ,Germanium ,Space (mathematics) ,01 natural sciences ,medicine.anatomical_structure ,chemistry ,Excited state ,0103 physical sciences ,medicine ,Level structure ,Atomic physics ,Nuclear Experiment ,010306 general physics ,Spin (physics) ,Nucleus ,Energy (signal processing) ,Excitation - Abstract
Excited states of the $^{61}\mathrm{Ni}$ ($Z=28,N=33$) nucleus have been probed using heavy-ion-induced fusion evaporation reaction and an array of Compton suppressed germanium (clover) detectors as detection system for the emitted $\ensuremath{\gamma}$ rays. Seventeen new transitions have been identified and placement of six transitions have been modified with respect to the previous measurements, following which the level scheme of the nucleus has been extended up to an excitation energy ${E}_{x}\ensuremath{\approx}7$ MeV and spin $\ensuremath{\approx}10\ensuremath{\hbar}$. Higher excitations involving the ${g}_{9/2}$ orbital in the $fpg$ model space have been established. The experimental results on the level structure of the nucleus have been interpreted in the light of large basis shell model calculations that lead to an understanding of the single particle configurations underlying the level structure of the nucleus. The comparison can be suggestive of further refinements in the shell model interactions for better overlap of the theoretical results with the experimental data.
- Published
- 2019
35. Observation of isoscalar multipole strengths in exotic doubly-magic 56Ni in inelastic α scattering in inverse kinematics
- Author
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N.L. Achouri, Marine Vandebrouck, S. Damoy, Elias Khan, H. Bouzomita, M. Fujiwara, K. Mazurek, L. Caceres, J. F. Libin, J. Van de Walle, M. Caamaño, U. Garg, S. M. Lukyanov, H. Savajols, A. Krasznahorkay, J. Pancin, K. Boretzky, B. Bastin, S. Bagchi, G. F. Grinyer, G. Lhoutellier, C. Stodel, Riccardo Raabe, L. Suen, J. Gibelin, Nasser Kalantar-Nayestanaki, Catherine Rigollet, Hidetoshi Akimune, S. Sambi, J. C. Thomas, O. Kamalou, L. Perrot, M. A. Najafi, T. Roger, M. Senoville, F. Delaunay, B. Fernández-Domínguez, Y. E. Penionzhkevich, M.N. Harakeh, Universidade de Santiago de Compostela. Departamento de Física de Partículas, KVI-CART, University of Groningen, University of Groningen [Groningen], Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Universidade de Santiago de Compostela [Spain] (USC ), Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institute for Nuclear Research [Budapest] (ATOMKI), Hungarian Academy of Sciences (MTA), Flerov Laboratory of Nuclear Reactions [Dubna] (FLNR), Joint Institute for Nuclear Research (JINR), Instituut voor Kern-en Stralingsfysica (IKS), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), GANILEXP, Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Research unit Nuclear & Hadron Physics
- Subjects
Nuclear and High Energy Physics ,Isoscalar ,ACTIVE TARGET ,Nuclear Theory ,Magnetic monopole ,[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] ,Resonance (particle physics) ,NUCLEAR INCOMPRESSIBILITY ,Nuclear physics ,ENERGY ,ddc:530 ,Nuclear Experiment ,Physics ,Inverse kinematics ,Isotope ,Scattering ,BEAMS ,lcsh:QC1-999 ,3. Good health ,Dipole ,ISOTOPES ,DIPOLE RESONANCE ,Atomic physics ,Multipole expansion ,MATTER ,lcsh:Physics - Abstract
The Isoscalar Giant Monopole Resonance (ISGMR) and the Isoscalar Giant Dipole Resonance (ISGDR) compression modes have been studied in the doubly-magic unstable nucleus 56Ni. They were measured by inelastic α-particle scattering in inverse kinematics at 50MeV/u with the MAYA active target at the GANIL facility. The centroid of the ISGMR has been obtained at Ex=19.1 ±0.5MeV. Evidence for the low-lying part of the ISGDR has been found at Ex=17.4 ±0.7MeV. The strength distribution for the dipole mode shows similarity with the prediction from the Hartree–Fock (HF) based random-phase approximation (RPA)[1]. These measurements confirm inelastic α-particle scattering as a suitable probe for exciting the ISGMR and the ISGDR modes in radioactive isotopes in inverse kinematics This work was supported by the European Commission within the Seventh Framework Programme through IA-ENSAR (contract No. RII3-CT-2010-262010) and GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany, and the United States National Science Foundation (Grants Number PHY-1068192 and PHY-1419765) SI
- Published
- 2015
36. Lifetime measurement and shell model description of negative parity states up to band-termination in 49V
- Author
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Bency John, S. Saha, S. Mukhopadhyay, L. S. Danu, Y. K. Gupta, R. Chakrabarti, G. K. Prajapati, S. K. Tandel, Dwaipayan Biswas, U. Garg, B. N. Joshi, J. Sethi, and R. Palit
- Subjects
Physics ,Nuclear and High Energy Physics ,Valence (chemistry) ,Spectrometer ,010308 nuclear & particles physics ,Attenuation ,Yrast ,SHELL model ,Parity (physics) ,01 natural sciences ,symbols.namesake ,Atomic orbital ,0103 physical sciences ,symbols ,Atomic physics ,010306 general physics ,Doppler effect - Abstract
The yrast and a few of the yrare negative-parity states in the 49V nucleus have been investigated employing the 27Al(28Si, α2p)49V reaction. Most of the levels and the deexciting γ rays, reported earlier in 49V, have been observed in this measurement using the Indian National Gamma Array (INGA) spectrometer. Mean lifetimes up to the band-terminating state have been extracted following Doppler Shift Attenuation Method (DSAM), and reduced transition probabilities have been deduced. Large Scale Shell Model (LSSM) calculations in the full fp shell employing various effective interactions with no restrictions imposed on the valence orbitals have been performed. The results that have been obtained from calculations are in fair agreement with the experimentally obtained values.
- Published
- 2020
37. The ( Li6,Li*6[3.56MeV] ) reaction at 100 MeV/u as a probe of Gamow-Teller transition strengths in the inelastic scattering channel
- Author
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J. C. Zamora, Eiji Ideguchi, S. Zhu, Hooi Jin Ong, A. Inoue, R. G. T. Zegers, Takeshi Koike, T. H. Hoang, Atsushi Tamii, Shumpei Noji, Mohsen Harakeh, Chihiro Iwamoto, G. Gey, R. Titus, X. K. Zhou, Y. D. Fang, C. Kacir, M. L. Liu, S. Lipschutz, N. Ichige, Nobuyuki Kobayashi, M. Kumar Raju, J. Pereira, C. J. Guess, Johann Isaak, J. Schmitt, M. P. Carpenter, Nori Aoi, Sam M. Austin, D. Bazin, P. von Neumann-Cosel, Y. Yamamoto, C. Sullivan, J. J. Carroll, Hisanori Fujita, V. Werner, E. Hudson, and U. Garg
- Subjects
Physics ,Isovector ,010308 nuclear & particles physics ,Scattering ,Isoscalar ,Nuclear Theory ,Gamma ray ,Inelastic scattering ,01 natural sciences ,Nuclear physics ,0103 physical sciences ,r-process ,Neutrino ,Nuclear Experiment ,010306 general physics ,Excitation - Abstract
Background: Inelastic neutrino-nucleus scattering is important for understanding core-collapse supernovae and the detection of emitted neutrinos from such events in earth-based detectors. Direct measurement of the cross sections is difficult and has only been performed on a few nuclei. It is, therefore, important to develop indirect techniques from which the inelastic neutrino-nucleus scattering cross sections can be determined. Purpose: This paper presents a development of the (Li-6,Li-6*[T = 1, T-z = 0, 0(+), 3.56 MeV]) reaction at 100 MeV/u as a probe for isolating the isovector spin-transfer response in the inelastic channel (Delta S = 1, Delta T = 1, Delta T-z = 0) from which the Gamow-Teller transition strengths from nuclei of relevance for inelastic neutrino-nucleus scattering cross sections can be extracted. Method: By measuring the Li-6 ejectile in a magnetic spectrometer and selecting events in which the 3.56 MeV gamma ray from the decay of the Li-6*[3.56 MeV] state is detected, the isovector spin-transfer selectivity is obtained. High-purity germanium clover detectors served to detect the gamma rays. Doppler reconstruction was used to determine the gamma energy in the rest frame of Li-6. From the Li-6 and 3.56 MeV gamma-momentum vectors the excitation energy of the residual nucleus was determined. Results: In the study of the C-12(Li-6,Li-6*[3.56 MeV]) reaction, the isovector spin-transfer excitation-energy spectrum in the inelastic channel was successfully measured. The strong Gamow-Teller state in C-12 at 15.1 MeV was observed. Comparisons with the analog C-12(Li-6,He-6) reaction validate the method of extracting the Gamow-Teller strength. In measurements of the Mg-24, Nb-93(Li-6,Li-6*[3.56 MeV]) reactions, the 3.56 MeV gamma peak could not be isolated from the strong background in the gamma spectrum from the decay of the isoscalar excitations. It is argued that by using a gamma-ray tracking array instead of a clover array, it is feasible to extend the mass range over which the (Li-6,Li-6*) reaction can be used for extracting the isovector spin-transfer response up to mass numbers of similar to 25 and perhaps higher. Conclusions: It is demonstrated that the (Li-6,Li-6*[3.56 MeV]) reaction probe can be used to isolate the inelastic isovector spin-transfer response in nuclei. Application to nuclei with mass numbers of about 25 or more, however, will require a more efficient gamma-ray array with a better tracking capability.
- Published
- 2018
38. Possible onset of multifaceted excitation modes in Al29
- Author
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U. Garg, S. Das, R. Raut, S. S. Ghugre, A. Chakraborty, Ratnajit Bhattacharjee, A. K. Sinha, R. Chakrabarti, S. Saha, M. A. Khan, J. Sethi, H. Sultana, S. S. Bhattacharjee, R. Palit, S. Samanta, and Trupti H Trivedi
- Subjects
Physics ,Fusion ,010308 nuclear & particles physics ,Attenuation ,Approx ,Space (mathematics) ,01 natural sciences ,Molecular physics ,0103 physical sciences ,Level structure ,010306 general physics ,Axial symmetry ,Magnetic dipole ,Excitation - Abstract
This paper reports on an investigation on the level structure of the odd-mass $^{29}\mathrm{Al}$ nucleus populated via heavy-ion induced fusion evaporation reaction. Rotational sequences with fast magnetic dipole transitions have been identified. These sequences exhibit the essential characteristic features of magnetic-rotation-like behavior, which has been corroborated through lifetime measurements using the Doppler shift attenuation method. The sequences also show features exhibited by axially deformed nuclei. Thus, the level structure presents the possibility of existence of multifaceted excitation modes in $^{29}\mathrm{Al}$, which are believed to be the first of its kind observed in the $A\ensuremath{\approx}$ 30 region. Shell model calculations, carried out within the $sd$-model space, qualitatively reproduce the experimental observations.
- Published
- 2018
39. Isoscalar giant monopole, dipole, and quadrupole resonances in Zr90,92 and Mo92
- Author
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M. Fujiwara, Y. K. Gupta, S. Ando, M. Şenyiğit, S. Adachi, Tatsuya Furuno, K. B. Howard, Mohsen Harakeh, Takeo Kawabata, Nasser Kalantar-Nayestanaki, Yohei Matsuda, C. Iwamoto, M. Itoh, Takatoshi Aoki, Hidetoshi Akimune, U. Garg, J. T. Matta, Atsushi Tamii, C. Kadono, M. Tsumura, A. Uchiyama, and T. Nakahara
- Subjects
Physics ,010308 nuclear & particles physics ,Scattering ,Isoscalar ,Nuclear Theory ,Magnetic monopole ,01 natural sciences ,7. Clean energy ,Spectral line ,Dipole ,0103 physical sciences ,Quadrupole ,Atomic physics ,010306 general physics ,Nuclear theory ,Beam energy - Abstract
The isoscalar giant monopole, dipole, and quadrupole strength distributions have been deduced in $^{90,92}\mathrm{Zr}$ and $^{92}\mathrm{Mo}$ from ``background-free'' spectra of inelastic $\ensuremath{\alpha}$-particle scattering at a beam energy of 385 MeV at extremely forward angles, including ${0}^{\ensuremath{\circ}}$. These strength distributions were extracted by a multipole-decomposition analysis based on the expected angular distributions of the respective multipoles. All these strength distributions for the three nuclei practically coincide with each other, affirming that giant resonances, being collective phenomena, are not influenced by nuclear shell structure near $A\ensuremath{\sim}90$, contrary to the claim in a recent measurement.
- Published
- 2018
40. Single-particle excitations in the level structure of Cu64
- Author
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Subhasis Samanta, S. Biswas, N. Kumar, Sandeep Chatterjee, Md. S. R. Laskar, Neelam, S. S. Ghugre, S. K. Das, U. Garg, S. Saha, R. Raut, F. S. Babra, R. Palit, Purnima Singh, A. K. Sinha, P. Jones, and Ratnajit Bhattacharjee
- Subjects
Physics ,010308 nuclear & particles physics ,Excited state ,0103 physical sciences ,Level structure ,Particle ,Atomic physics ,Nuclear Experiment ,010306 general physics ,01 natural sciences ,Excitation ,Energy (signal processing) ,Spin-½ - Abstract
Excited states of the $^{64}\mathrm{Cu}\phantom{\rule{4pt}{0ex}}(Z=29,N=35)$ nucleus have been probed using heavy-ion-induced fusion evaporation reaction and an array of Compton-suppressed Clovers as detection system for the emitted $\ensuremath{\gamma}$ rays. More than 50 new transitions have been identified and the level scheme of the nucleus has been established up to an excitation energy ${E}_{x}\phantom{\rule{4pt}{0ex}}\ensuremath{\sim}\phantom{\rule{4pt}{0ex}}6$ MeV and spin $\ensuremath{\sim}10\ensuremath{\hbar}$. The experimental results have been compared with those from large-basis shell-model calculations that facilitated an understanding of the single-particle configurations underlying the level structure of the nucleus.
- Published
- 2018
41. Splitting of ISGMR strength in the light-mass nucleus 24Mg due to ground-state deformation
- Author
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S. Kishi, Hidetoshi Akimune, U. Garg, D. Patel, J. T. Matta, S. Terashima, Masatoshi Itoh, Takahiro Kawabata, K. Nakanishi, Y. Yasuda, Hitoshi Hashimoto, T. Peach, M. Fujiwara, J. Hoffman, Harutaka Sakaguchi, Mohsen Harakeh, Kenichi Yoshida, M. Yosoi, K. Hara, T. Murakami, Y.K. K Gupta, Masaki Uchida, and Research unit Nuclear & Hadron Physics
- Subjects
Nuclear and High Energy Physics ,Nuclear Theory ,GIANT MONOPOLE RESONANCE ,Isoscalar ,FOS: Physical sciences ,Inelastic scattering ,01 natural sciences ,Resonance (particle physics) ,COUPLED-CHANNELS CALCULATIONS ,Nuclear Theory (nucl-th) ,ENERGY ,0103 physical sciences ,EXCITATION ,SCATTERING ,Nuclear Experiment (nucl-ex) ,010306 general physics ,Nuclear Experiment ,Physics ,010308 nuclear & particles physics ,Scattering ,lcsh:QC1-999 ,DIPOLE RESONANCE ,PB-208 ,Deformation (engineering) ,Atomic physics ,Microscopic theory ,Ground state ,Excitation ,lcsh:Physics - Abstract
The isoscalar giant monopole resonance (ISGMR) strength distribution in $^{24}$Mg has been determined from background-free inelastic scattering of 386-MeV $\alpha$ particles at extreme forward angles, including 0$^{\circ}$. The ISGMR strength distribution has been observed for the first time to have a two-peak structure in a light-mass nucleus. This splitting of ISGMR strength is explained well by microscopic theory in terms of the prolate deformation of the ground state of $^{24}$Mg., Comment: 5 pages, 4 figures; to be published in Phys. Lett. B
- Published
- 2015
42. High-spin states in Cs133 and the shell model description
- Author
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Anil Raghav, Md. S. R. Laskar, B. S. Naidu, S. Sihotra, V. V. Parkar, P. K. Joshi, H. C. Jain, Z. Naik, A. Y. Deo, Sathi Sharma, Savita Jadhav, R. Donthi, S. Biswas, S. Saha, G. Mukherjee, J. Sethi, D. Mehta, U. Garg, P. C. Srivastava, R. Palit, S. Kumar, Anindya Goswami, and F. S. Babra
- Subjects
Physics ,Spin states ,010308 nuclear & particles physics ,0103 physical sciences ,SHELL model ,Atomic physics ,010306 general physics ,01 natural sciences ,Beam energy ,Energy (signal processing) - Abstract
The high-spin states in $^{133}\mathrm{Cs}$, populated using the reaction $^{130}\mathrm{Te}(^{7}\mathrm{Li},4n)$ with 45-MeV beam energy, have been extended up to an excitation energy of 5.265 MeV using the Indian National Gamma Array. The observed one- and three-quasiparticle bands in $^{133}\mathrm{Cs}$, built on the $\ensuremath{\pi}{h}_{11/2},\phantom{\rule{0.28em}{0ex}}\ensuremath{\pi}{g}_{7/2}$, $\ensuremath{\pi}{d}_{5/2}$; and ${(\ensuremath{\pi}{g}_{7/2}\ensuremath{\pi}{d}_{5/2})}^{1}\ensuremath{\bigotimes}\ensuremath{\nu}{h}_{11/2}^{\ensuremath{-}2}$ configurations, respectively, have similar structure as seen in the lighter odd-$A$ Cs isotopes. The experimental level scheme has been compared with the large-scale shell model calculation without truncation using the $jj55pna$ interaction, showing a good agreement for both positive- and negative-parity states.
- Published
- 2017
43. Band structures in Pd101
- Author
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D. Mehta, U. Garg, J. Sethi, S. Sihotra, S. Kumar, K. P. Singh, S. Saha, G. H. Bhat, Manjit Kaur, Jatinder Goswamy, J. A. Sheikh, N. K. Singh, Sham S. Malik, Varinderjit Singh, and R. Palit
- Subjects
Physics ,010308 nuclear & particles physics ,Excited state ,0103 physical sciences ,SHELL model ,Quasiparticle ,Band crossing ,Atomic physics ,010306 general physics ,Spin (physics) ,01 natural sciences - Abstract
Excited states in the $^{101}\mathrm{Pd}$ nucleus were investigated through the $^{75}\mathrm{As}(^{31}\mathrm{P},2p3n)$ fusion-evaporation reaction at ${E}_{\mathrm{lab}}=125$ MeV by using the Indian National Gamma Array spectrometer equipped with 21 clover Ge detectors. The level scheme is considerably extended for medium spin values. New positive-parity band structures in $^{101}\mathrm{Pd}$ have been studied within the framework of the projected shell model and are found to undergo transition from single quasiparticle to high-$K$ three quasiparticle configuration after band crossing, i.e., from principal-axis rotation to tilted-axis rotation. The negative-parity band structures are discussed in the framework of the hybrid version of tilted-axis cranking shell model calculations. The observed alignment gain in the lowest excited $\ensuremath{\nu}{h}_{11/2}$ negative-parity band results from successive ${(\ensuremath{\nu}{g}_{7/2})}^{2}$ and ${(\ensuremath{\pi}{g}_{9/2})}^{2}$ pair alignments. The higher excited negative-parity bands are reproduced for the $\ensuremath{\nu}[{h}_{11/2}{({g}_{7/2}/{d}_{5/2})}^{2}]$ and ${(\ensuremath{\pi}{g}_{9/2})}^{\ensuremath{-}2}\ensuremath{\bigotimes}\ensuremath{\nu}{h}_{11/2}$ configurations.
- Published
- 2017
44. Observation of the Isovector Giant Monopole Resonance via the Si28(Be10,B*10[1.74 MeV]) Reaction at 100 AMeV
- Author
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Sam M. Austin, C. M. Campbell, Shumpei Noji, C. Morse, C. Loelius, U. Garg, M. Bowry, S. Lipschutz, B. A. Brown, Remco Zegers, C. Sullivan, D. Weisshaar, E. Lunderberg, T. Redpath, C. Robin, Yoshiko Sasamoto, E. Kwan, M.N. Harakeh, Hideyuki Sakai, C. Langer, Masaki Sasano, G. Perdikakis, S. Gales, Elena Litvinova, M. Scott, J. A. Tostevin, Daniel Bazin, Alexandra Gade, Tomohiro Uesaka, and R.M. Almus
- Subjects
Physics ,Isovector ,010308 nuclear & particles physics ,Nuclear Theory ,Cyclotron ,Magnetic monopole ,General Physics and Astronomy ,Resonance ,Nuclear matter ,01 natural sciences ,7. Clean energy ,law.invention ,Nuclear physics ,Dipole ,law ,0103 physical sciences ,Atomic physics ,Born approximation ,Nuclear Experiment ,010306 general physics ,Excitation - Abstract
The (10Be,10B [1.74 MeV]) charge-exchange reaction at 100 AMeV is presented as a new probe for isolating the isovector (ΔT = 1) non-spin-transfer (ΔS = 0) response of nuclei, with 28Si being the rst nucleus studied. By using a secondary 10Be beam produced by fast fragmentation of 18O nuclei at the NSCL Coupled Cyclotron Facility, applying the dispersion-matching technique with the S800 magnetic spectrometer to determine the excitation energy in 28Al, and performing high- resolution -ray tracking with the Gamma-Ray Energy Tracking Array (GRETINA) to identify the 1022-keV ray associated with the decay from the 1.74-MeV T = 1 isobaric analog state in 10B, a ΔS = 0 excitation-energy spectrum in 28Al was extracted. Monopole and dipole contributions were determined through a multipole-decomposition analysis, and the isovector giant dipole (IVGDR) and monopole (IVGMR) resonances were identi ed. The results show that this probe is a powerful tool for studying the elusive IVGMR, which is of interest for performing stringent tests of modern density functional theories at high excitation energies and for constraining the bulk properties of nuclei and nuclear matter. The extracted distributions were compared with theoretical calculations based on the normal-modes formalism and the proton-neutron relativistic time-blocking approximation. Calculated cross sections based on these strengths underestimate the data by about a factor of two, which likely indicates de ciencies in the reaction calculations based on the distorted wave Born approximation.
- Published
- 2017
45. Validation, quality control, and compliance practice for mass spectrometry assays in the clinical laboratory
- Author
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Douglas F. Stickle and U. Garg
- Subjects
Engineering ,medicine.medical_specialty ,business.industry ,media_common.quotation_subject ,010401 analytical chemistry ,Control (management) ,Professional practice ,030226 pharmacology & pharmacy ,01 natural sciences ,Method development ,0104 chemical sciences ,Food and drug administration ,03 medical and health sciences ,0302 clinical medicine ,Proficiency testing ,medicine ,Quality (business) ,Medical physics ,business ,Accreditation ,Pharmaceutical industry ,media_common - Abstract
Clinical laboratory assays using mass spectrometry are invariably developed in-house. Careful attention must therefore be given to both regulatory requirements and standards of professional practice regarding the validation, quality control, and competency/compliance aspects of offering, such assays. Here we review multiple guidelines and sources of information regarding this process: from federal requirements of the Clinical Laboratory Improvement Act (CLIA), accreditation requirements of the College of American Pathologists (CAP), Food and Drug Administration (FDA) guidance related to the pharmaceutical industry, and recommendations/reviews from the literature. We also discuss proposals for new FDA regulations regarding laboratory-developed tests (LDTs) that may have dramatic impact on clinical laboratories that utilize mass spectrometry. Only liquid and gas-chromatography mass spectrometry are discussed in this chapter.
- Published
- 2017
46. Disorders of trace metals
- Author
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U. Garg and L.D. Smith
- Subjects
0301 basic medicine ,Inorganic chemistry ,chemistry.chemical_element ,Manganese ,Zinc ,Micronutrient ,medicine.disease ,Intestinal absorption ,Trace (semiology) ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,chemistry ,Environmental chemistry ,medicine ,Trace metal ,Menkes disease ,030217 neurology & neurosurgery ,Selenium - Abstract
Trace metals are inorganic micronutrients that are required, by humans, in very low concentrations. They act as cofactors for the proper functioning of many enzymes and other proteins. Their deficiency leads to specific signs and symptoms. Sometimes trace metals deficiency is not dietary, but is due to defects in intestinal absorption, transport, or recycling. Direct measurement of trace metals or other tests such as enzyme assays and molecular testing are used to confirm the clinical suspicion of trace metal deficiency. In this chapter, metabolic disorders of various trace metals including zinc, copper, molybdenum, manganese, and selenium are discussed. Confounding factors that may mimic trace metal deficiency are also discussed.
- Published
- 2017
47. Urea cycle and other disorders of hyperammonemia
- Author
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U. Garg and L.D. Smith
- Subjects
0301 basic medicine ,medicine.medical_specialty ,Orotic acid ,Arginine ,Chemistry ,medicine.medical_treatment ,Hyperammonemia ,Urine ,medicine.disease ,Arginase ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Endocrinology ,Low-protein diet ,Internal medicine ,Urea cycle ,medicine ,030211 gastroenterology & hepatology ,medicine.drug ,Urine organic acids - Abstract
Hyperammonemia, characterized by excess ammonia in the blood, can be a life-threatening condition. Clinical symptoms are nonspecific, and include poor feeding, lethargy, irritability, tachypnea, seizures, obtundation, and respiratory insufficiency. Hyperammonemia is due to defect in detoxification or overproduction of ammonia. Defects in the urea cycle lead to the most severe hyperammonemia. Other causes of hyperammonemia include various metabolic defects such as certain organic acidurias, fatty acid oxidation defects, drugs and liver disease. The most important diagnostic test for the diagnosis of hyperammonemia is measuring plasma ammonia. Various biomarkers are used for the differential diagnosis of hyperammonia. They include plasma and urine amino acid profiles, urine organic acid profiles, and plasma acylcarnitine profiles. Management of acute hyperammonia includes discontinuation of protein intake, and treatment with nitrogen scavengers and glucose. Arginine is administrated in all urea cycle defects except arginase deficiency. Disease follow-up biomarkers include plasma ammonia levels, specific amino acids, and urine orotic acid. Since patients are on a low protein diet, markers of nutritional deficiency are also monitored.
- Published
- 2017
48. List of Contributors
- Author
-
R. Artuch, M.J. Bennett, N. Couser, M. Dasouki, P.D. DeArmond, D.J. Dietzen, A.M. Ferguson, R. Ganetzky, A. Garcia-Cazorla, U. Garg, M. Gucsavas-Calikoglu, M. He, L. Hubert, P.M. Jones, S.F. Lo, M. Molero-Luis, M.A. Morrissey, A. Ormazabal, A.L. Pyle-Eilola, F.J. Reynoso, L.D. Smith, Q. Sun, V.R. Sutton, and C. Yu
- Published
- 2017
49. Disorders of vitamins and cofactors
- Author
-
L.D. Smith and U. Garg
- Subjects
0301 basic medicine ,Vitamin ,medicine.medical_specialty ,nutritional and metabolic diseases ,Riboflavin ,Pyridoxine ,Cobalamin ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,0302 clinical medicine ,Endocrinology ,chemistry ,Biochemistry ,Internal medicine ,Pantothenic acid ,medicine ,Thiamine ,Vitamin B12 ,030217 neurology & neurosurgery ,Niacin ,medicine.drug - Abstract
Vitamins and cofactors are essential for the health and development of humans. Most are not synthesized by humans and must be obtained from exogenous sources. They are involved in a number of biochemical functions, mostly as enzyme cofactors. For their actions, they must be transported to specific intracellular sites. Deficiencies of vitamins and cofactors could be nutritional or due to inborn errors of metabolism of intracellular recycling or storage. In this chapter, inborn errors of metabolism of various vitamins and cofactors including thiamine (vitamin B1), riboflavin (vitamin B2), niacin (vitamin B3), pantothenic acid (vitamin B5), pyridoxine (vitamin B6), biotin (vitamin B7), and cobalamin (vitamin B12) are discussed. Confounding factors that may mimic inborn errors of metabolism are also discussed.
- Published
- 2017
50. List of Contributors
- Author
-
L.M. Bachmann, W. Clarke, J.C. Cook-Botelho, C.A. Crutchfield, D. French, U. Garg, D.A. Herold, P.J. Jannetto, H. Ketha, P.B. Kyle, K.L. Lynch, I.W. Martin, H. Nair, B. Rappold, R.J. Singh, D.F. Stickle, J. Stone, and J.Y. Yang
- Published
- 2017
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