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Journal of Physics G : Nuclear and Particle Physics
Journal Prestige (SJR): 1.513

Citation Impact (citeScore): 3
Number of Followers: 16

This is an Open Access Journal

Open Access journal
ISSN (Print) 0954-3899 - ISSN (Online) 1361-6471
Published by IOP

[43 journals]

Fusion of 12C + 24Mg at extreme sub-barrier energies
- Authors: G Montagnoli; A M Stefanini, C L Jiang, K Hagino, F Niola, D Brugnara, P Čolović, G Colucci, L Corradi, R Depalo, E Fioretto, A Goasduff, G Pasqualato, F Scarlassara, S Szilner I Zanon
  First page: 095101
  Abstract: A recent experiment on 12 C + 24 Mg sub-barrier fusion was performed. Standard coupled-channels calculations clearly over-estimated the low energy cross sections and there was indication of a maximum of the astrophysical S factor vs energy. In the present work further measurements have been performed on the same system, and we extended the excitation function to lower energies down to σ ≃ 4 μ b, confirming the existence of the hindrance phenomenon. Additional energy points near the barrier were added as well. In agreement with the result of previous experiment, the hindrance energy threshold is observed to correspond to a remarkably large cross section. The present new data allow to better define the S -factor maximum, that is well fitted using two parametrizations of either the hindrance or the adiabatic model. We also performed coupled-channels calculations using a Woods–Saxon potential. Far below the barrier we observe that the coupling strengths decrease and tend to vanish, indeed one-dimensional tunnelling calculations well reproduce the excitation function. Further precise cross section measurements at slightly lower energies are needed to discriminate between the adiabatic and hindrance models. This would give a reliable guidance for the extrapolation to the systems of astrophysical interest, like 12 C + 12 C and 16 O + 16 O.
  Citation: Journal of Physics G: Nuclear and Particle Physics
  PubDate: 2022-07-20T23:00:00Z
  DOI: 10.1088/1361-6471/ac7edd
  Issue No: Vol. 49, No. 9 (2022)
The PDF4LHC21 combination of global PDF fits for the LHC Run III*
- Authors: Richard D Ball; Jon Butterworth, Amanda M Cooper-Sarkar, Aurore Courtoy, Thomas Cridge, Albert De Roeck, Joel Feltesse, Stefano Forte, Francesco Giuli, Claire Gwenlan, Lucian A Harland-Lang, T J Hobbs, Tie-Jiun Hou, Joey Huston, Ronan McNulty, Pavel M Nadolsky, Emanuele R Nocera, Tanjona R Rabemananjara, Juan Rojo, Robert S Thorne, Keping Xie, C-P Yuan The PDF4LHC Working Group
  First page: 080501
  Abstract: A precise knowledge of the quark and gluon structure of the proton, encoded by the parton distribution functions (PDFs), is of paramount importance for the interpretation of high-energy processes at present and future lepton–hadron and hadron–hadron colliders. Motivated by recent progress in the PDF determinations carried out by the CT, MSHT, and NNPDF groups, we present an updated combination of global PDF fits: PDF4LHC21. It is based on the Monte Carlo combination of the CT18, MSHT20, and NNPDF3.1 sets followed by either its Hessian reduction or its replica compression. Extensive benchmark studies are carried out in order to disentangle the origin of the differences between the three global PDF sets. In particular, dedicated fits based on almost identical theory settings and input datasets are performed by the three groups, highlighting the role played by the respective fitting methodologies. We compare the new PDF4LHC21 combination with its predecessor, PDF4LHC15, demonstrating their good overall consistency and a modest reduction of PDF uncertainties for key LHC processes such as electroweak gauge boson production and Higgs boson production in gluon fusion. We study the phenomenological implications of PDF4LHC21 for a representative selection of inclusive, fiducial, and differential cross sections at the LHC. The PDF4LHC21 combination is made available via the LHAPDF library and provides a robust, user-friendly, and efficient method to estimate the PDF uncertainties associated to theoretical calculations for the upcoming Run III of the LHC and beyond.
  Citation: Journal of Physics G: Nuclear and Particle Physics
  PubDate: 2022-07-04T23:00:00Z
  DOI: 10.1088/1361-6471/ac7216
  Issue No: Vol. 49, No. 8 (2022)
B − L model with A 4 × Z 3 × Z 4 symmetry for 3 + 1 active-sterile
neutrino mixing
- Authors: V V Vien
  First page: 085001
  Abstract: We construct a B − L model with A 4 × Z 3 × Z 4 flavor symmetry that accounts for the recent 3 + 1 active-sterile neutrino data. The tiny neutrino mass and the mass hierarchy are obtained by the type-I seesaw mechanism. The hierarchy of the lepton masses is satisfied by a factor of ##IMG## [https://cfn-live-content-bucket-iop-org.s3.amazonaws.com/journals/0954-3899/49/8/085001/revision2/gac6a70ieqn1.gif'AWSAccessKeyId=AKIAYDKQL6LTV7YY2HIK&Expires=1659656006&Signature=tmeU0c7c4VGnBYVOSfI9imvCfx4%3D] {${v}_{H}{\left(\frac{{v}_{l}}{{\Lambda}}\right)}^{2}\sim 1{0}^{-4}\enspace \mathrm{G}\mathrm{e}\mathrm{V}$} of the electron mass compared to the muon and tau masses of the order of ##IMG## [https://cfn-live-content-bucket-iop-org.s3.amazonaws.com/journals/0954-3899/49/8/085001/revision2/gac6a70ieqn2.gif'AWSAccessKeyId=AKIAYDKQL6LTV7YY2HIK&Expires=1659656006&Signature=LY3zrOtx1mr9AromT%2ByXlqZtBHw%3D] {$\frac{{v}_{H}{v}_{l}}{{\Lambda}}\sim 1{0}^{-1}\enspace \mathrm{G}\mathrm{e}\mathrm{V}$} . The 3 + 1 active-sterile neutrino mixings are predicted to be 0.015 ⩽ U 14 2 ⩽ 0.045, 0.004 ⩽ U 24 2 ⩽ 0.012 and 0.004 ⩽ U 34 2 ⩽ 0.014 for normal hierarchy while 0.020 ⩽ U 14 2 ⩽ 0.045, 0.008 ⩽ U 24 2 ⩽ 0.018 and 0.008 ⩽ U 34 2 ⩽ 0.022 for inverted hierarchy. Sterile neutrino masses are predicted to be 0.7 ≲ m s (eV) ≲ 3.16 for normal hierarchy and 2.6 ≲ m s (eV) ≲ 7.1 for inverted hierarchy. For three neutrino scheme the model predicts 0.3401 ⩽ sin 2 θ 12 ⩽ 0.3415, 0.460 ⩽ sin 2 θ 23 ⩽ 0.540, −0.60 ⩽ sin δ CP ⩽ −0.20 for normal hierarchy and 0.3402 ⩽ sin 2 θ 12 ⩽ 0.3416, 0.434 ⩽ sin 2 θ 23 ⩽ 0.610, −0.95 ⩽ sin δ CP ⩽ − 0.60 for inverted hierarchy.
  Citation: Journal of Physics G: Nuclear and Particle Physics
  PubDate: 2022-07-05T23:00:00Z
  DOI: 10.1088/1361-6471/ac6a70
  Issue No: Vol. 49, No. 8 (2022)
Pair production of neutral Higgs particles in the B-LSSM
- Authors: Dan He; Tai-Fu Feng, Jin-Lei Yang, Guo-Zhu Ning, Hai-Bin Zhang Xing-Xing Dong
  First page: 085002
  Abstract: Higgs pair production provides a unique handle for measuring the strength of Higgs self interaction and constraining the shape of the Higgs potential. Including radiative corrections to the trilinear couplings of CP -even Higgs, we investigate the cross section of the lightest neutral Higgs pair production in gluon fusion at the Large Hadron Collider in the supersymmetric extensions of the standard model. Numerical results indicate that the correction to the cross section is about 11% in the B-LSSM, while is only about 4% in the MSSM. Considering the constraints of the experimental data of the lightest Higgs, we find that the gauge couplings of U (1) B – L and the ratio of the nonzero vacuum expectation values of two singlets also affect strongly the theoretical evaluations on the production cross section in the B-LSSM.
  Citation: Journal of Physics G: Nuclear and Particle Physics
  PubDate: 2022-06-29T23:00:00Z
  DOI: 10.1088/1361-6471/ac77a8
  Issue No: Vol. 49, No. 8 (2022)
Production of Chern–Simons bosons in decays of mesons
- Authors: Yuliia Borysenkova; Pavlo Kashko, Mariia Tsarenkova, Kyrylo Bondarenko Volodymyr Gorkavenko
  First page: 085003
  Abstract: We consider the effective interaction of quarks with a new GeV-scale vector particle that couples to electroweak gauge bosons by the so-called effective Chern–Simons (CS) interaction. We call this particle the CS boson. We construct effective Lagrangian of the CS boson interaction with quarks of two different flavors. This interaction is given by a divergent loop diagram, however, it turns out that the divergent part is equal to zero as a consequence of the CKM matrix unitarity in the SM. Therefore, we are able to predict effective interaction of the CS boson with quarks of different flavors without introducing new unknown parameters to the model, using only parameters of the initial effective Lagrangian. Our result shows that the effective interaction of the CS boson with down-type quarks is sufficiently stronger compared with up-type quarks. Based on our results, we give a prediction for the production of CS bosons in mesons decays. Branching fractions were obtained for the main reactions of the CS production in meson decays. The results obtained will be useful for searching for the long-lived GeV-scale CS boson in intensity frontier experiments.
  Citation: Journal of Physics G: Nuclear and Particle Physics
  PubDate: 2022-06-29T23:00:00Z
  DOI: 10.1088/1361-6471/ac77a7
  Issue No: Vol. 49, No. 8 (2022)
Slight excess at 130 GeV in search for a charged Higgs boson decaying to a
charm quark and a bottom quark at the Large Hadron Collider
- Authors: A G Akeroyd; Stefano Moretti Muyuan Song
  First page: 085004
  Abstract: Searches for a charged Higgs boson ( H ± ) decaying to a charm quark and a bottom quark ( H ± → cb ) have been carried out at the Large Hadron Collider (LHC) in the decay of top quarks ( t → H ± b ). In a recent search by the ATLAS collaboration (with all run II data, 139 fb −1 ) a local excess of around 3 σ has been observed, which is best fitted by a charged Higgs boson with a mass ##IMG## [https://cfn-live-content-bucket-iop-org.s3.amazonaws.com/journals/0954-3899/49/8/085004/revision2/gac77a6ieqn1.gif'AWSAccessKeyId=AKIAYDKQL6LTV7YY2HIK&Expires=1659656006&Signature=mkfGG0%2B2q2zHypbKAdB88IybpSg%3D] {$({m}_{{H}^{\pm }})$} of around 130 GeV and a product of branching ratios (BRs) given by BR( t → H ± b ) × BR( H ± → cb ) = 0.16% ± 0.06%. In the context of two-Higgs-doublet models (2HDM) with independent Yukawa couplings for H ± we present the parameter space for which this excess (assuming it to be genuine) can be accommodated, taking into account the limits from LHC searches for H ± → cs and H ± → τν at ##IMG## [https://cfn-live-content-bucket-iop-org.s3.amazonaws.com/journals/0954-3899/49/8/085004/revision2/gac77a6ieqn2.gif'AWSAccessKeyId=AKIAYDKQL6LTV7YY2HIK&Expires=1659656006&Signature=y0ZUm%2B7YVN4mGJYB5w8WlLC9R58%3D] {${m}_{{H}^{\pm }}$} = 130 GeV and the constraint from b → sγ . It is then shown that such an excess cannot be explained in 2HDMs with natural flavour conservation, but can be accommodated in the flipped three-Higgs-doublet model (3HDM) and in the aligned 2HDM (A2HDM). Upcoming searches with 139 fb −1 in the channels H ± → cb (CMS), H ± → cs (ATLAS/CMS) and H ± → τν (ATLAS/CMS) will determine if the excess is the first sign of an H ± with ##IMG## [https://cfn-live-content-bucket-iop-org.s3.amazonaws.com/journals/0954-3899/49/8/085004/revision2/gac77a6ieqn3.gif'AWSAccessKeyId=AKIAYDKQL6LTV7YY2HIK&Expires=1659656006&Signature=jwzeVViy%2BZDm%2FHDIXDBxnWtVk3A%3D] {${m}_{{H}^{\pm }}=130$} GeV.
  Citation: Journal of Physics G: Nuclear and Particle Physics
  PubDate: 2022-06-29T23:00:00Z
  DOI: 10.1088/1361-6471/ac77a6
  Issue No: Vol. 49, No. 8 (2022)
Prescription for finite oblique parameters S and U in extensions of the SM
with m W ≠ m Z cos θ W
- Authors: Francisco Albergaria; Luís Lavoura
  First page: 085005
  Abstract: We consider extensions of the standard model (SM) with neutral scalars in multiplets of SU (2) larger than doublets. When those scalars acquire vacuum expectation values, the resulting masses of the gauge bosons W ± and Z 0 are not related by m W = m Z cos θ W . In those extensions of the SM the oblique parameters S and U , when computed at the one-loop level, turn out to be either gauge-dependent or divergent. We show that one may eliminate this problem by modifying the Feynman rules of the SM for some vertices containing the Higgs boson; the modifying factors are equal to 1 in the limit m W = m Z cos θ W . We give the result for S in a model with arbitrary numbers of scalar SU (2) triplets with weak hypercharges either 0 or 1.
  Citation: Journal of Physics G: Nuclear and Particle Physics
  PubDate: 2022-07-13T23:00:00Z
  DOI: 10.1088/1361-6471/ac7a56
  Issue No: Vol. 49, No. 8 (2022)
Systematic shell model study for N = 82 and N = 126 isotones and nuclear
isomers
- Authors: Bharti Bhoy; Praveen C Srivastava
  First page: 085101
  Abstract: In the present work, we have done a systematic shell model study of N = 82 and N = 126 isotones. For the N = 82 isotones, we have performed calculations using SN100PN interaction, while for N = 126 isotones, we have used KHPE interaction. Similarities between these two isotonic chains have been reported, using the strong resemblance between the high- j orbitals. Apart from the nuclear spectroscopic properties, we have also explained different isomeric states in these two regions. In the N = 82 region, we have mainly discussed the properties of the 6 + and 17/2 + isomers, while in the N = 126 region for 8 + , 11 − , 21/2 − and 29/2 + isomers. We have reported B ( E 2), B ( E 3), g -factor, and quadrupole moments of the isomeric states for comparison in these two isotonic chains.
  Citation: Journal of Physics G: Nuclear and Particle Physics
  PubDate: 2022-06-27T23:00:00Z
  DOI: 10.1088/1361-6471/ac76da
  Issue No: Vol. 49, No. 8 (2022)
Bayesian evaluation of residual production cross sections in
proton-induced nuclear spallation reactions
- Authors: Dan Peng; Hui-Ling Wei, Xi-Xi Chen, Xiao-Bao Wei, Yu-Ting Wang, Jie Pu, Kai-Xuan Cheng Chun-Wang Ma
  First page: 085102
  Abstract: Residual production cross sections in spallation reactions are key data for nuclear physics and related applications. Spallation reactions are very complex due to the wide range of incident energies and abundant fragments involved. Therefore, it is challenging to obtain accurate and complete energy-dependent residual cross sections. With the guidance of a simplified EPAX formula (sEPAX), the Bayesian neural network (BNN) technique is applied to form a new machine learning model (BNN + sEPAX) for predicting fragment cross sections in proton-induced nuclear spallation reactions. Three types of sample dataset for measured residual production cross sections in proton-induced nuclear spallation reactions are made, i.e. D1 consists of isotopic cross sections in reactions below 1 GeV/u, D2 consists of fragments excitation functions of reactions up to 2.6 GeV/u, and D3 is a hybrid of D1 and D2. With the constructed BNN and BNN + sEPAX models, the isotopic and mass cross section distributions are compared for the 356 MeV/u 40 Ca + p and 1 GeV/u 136 Xe + p reactions, and fragment excitation functions in 40 Ca + p , 56 Fe + p , 138 Ba + p and 197 Au + p reactions. It is found that the BNN model needs sufficient information to achieve good extrapolations, while the BNN + sEPAX model performs better extrapolations based on less information due to the physical guidance of the sEPAX formulas. It is suggested that the BNN + sEPAX model provides a new approach to predict the energy-dependent residual production cross sections produced in proton-induced nuclear spallation reactions of incident energies from tens of MeV/u up to several GeV/u.
  Citation: Journal of Physics G: Nuclear and Particle Physics
  PubDate: 2022-06-27T23:00:00Z
  DOI: 10.1088/1361-6471/ac7069
  Issue No: Vol. 49, No. 8 (2022)
Corrigendum: Probing the sensitivity to leptonic δ CP in presence of
invisible decay of ν 3 using atmospheric neutrinos (2020 J. Phys. G:
Nucl. Part. Phys. 47 115004)
- Authors: Lakshmi S Mohan
  First page: 089501
  Citation: Journal of Physics G: Nuclear and Particle Physics
  PubDate: 2022-07-14T23:00:00Z
  DOI: 10.1088/1361-6471/ac72ba
  Issue No: Vol. 49, No. 8 (2022)