Journal of Physics G: Nuclear and Particle Physics最新文献

{"title":"Hydrodynamic model of heavy-ion collisions with low momentum components","authors":"A. Monnai","doi":"10.1088/1361-6471/ace3e0","DOIUrl":"https://doi.org/10.1088/1361-6471/ace3e0","url":null,"abstract":"\u0000 Relativistic heavy-ion collisions suggest that low momentum regions of the observed particle spectra are thermal and hydrodynamic, while medium-high momentum regions are non-thermal and perturbative. In this study, I construct a hydrodynamic model of heavy-ion collisions by cutting off the medium-high momentum contributions and investigate the phenomenological consequences. Numerical simulations indicate that the temperature of the quark matter can be higher at earlier times owing to the modification of the equation of state. It is also suggested that direct photon elliptic flow can be sensitive to the momentum dependence of thermalization.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45381355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating the role of electric fields on flow harmonics in heavy-ion collisions","authors":"Ankit Kumar Panda, R. Gangadharan, V. Roy","doi":"10.1088/1361-6471/acd39b","DOIUrl":"https://doi.org/10.1088/1361-6471/acd39b","url":null,"abstract":"\u0000 Using the blast-wave model, we explore the effect of electric fields on spectra and flow harmonics (especially the elliptic flow) for charged Pions and protons. We incorporate the first-order correction to the single-particle distribution function due to the electric fields and the dissipative effect while calculating the invariant yields of hadron in the Cooper-Frey prescription at the freezeout hypersurface. We find a noticeable correction to the directed and elliptic flow of Pions and protons for unidirectional and azimuthal asymmetric electric fields in the transverse plane of magnitude ∼ mπ2. Further, we observe mass dependency of the directed flow generated due to the electric fields. The splitting of particle and antiparticle’s elliptic flow is also discussed.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41948963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The decay A\u0000 0 → h\u0000 0\u0000 Z\u0000 (*) in the inverted hierarchy scenario and its detection prospects at the Large Hadron Collider","authors":"A. Akeroyd, S. Alanazi, S. Moretti","doi":"10.1088/1361-6471/ace3e1","DOIUrl":"https://doi.org/10.1088/1361-6471/ace3e1","url":null,"abstract":"\u0000 Searches are being carried out at the Large Hadron Collider (LHC) for the decay of the CP-odd scalar ($A^0$) in Two-Higgs-Doublet Models (2HDMs) with Natural Flavour Conservation (NFC) in the channel $A^0to h^0 Z$ (with $m_{h^0}=125$ GeV and $Z$ on-shell). In the absence of any signal, limits on the parameter space of $[tanbeta, cos(beta-alpha), m_{A^0}]$ in each 2HDM are derived for $m_{A^0} > 225$ GeV. In this work we consider the scenario of inverted hierarchy with $m_{h^0}<125$ GeV and $m_{H^0}=125$ GeV in which the decay $A^0to h^0 Z^{(*)}$ (i.e. including the case of an off-shell $Z$) can have a large branching ratio in the 2HDM (Type I) for $m_{A^0}<225$ GeV. We calculate the signal cross section $sigma(ggto A^0)times {rm BR}(A^0to h^0Z^{(*)})times {rm BR}(h^0to boverline b)$ in the 2HDM (Type I) with NFC and compare its magnitude with the cross section for the case of normal hierarchy ($m_{h^0}=125$ GeV) that is currently being searched for at the LHC. For the experimentally unexplored region $m_{A^0} < 225$ GeV it is shown that the above cross section for signal events in the scenario of inverted hierarchy can be of the order of a few picobarns. Such sizeable cross sections are several orders of magnitude larger than the cross sections for the case of normal hierarchy, thus motivating an extension of the ongoing searches for $A^0to h^0 Z^{(*)}$ to probe the scenario of inverted hierarchy.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49403510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quark-antiquark states of the lightest scalar mesons within the Nambu-Jona-Lasinio model with flavor-dependent coupling constants","authors":"F. Braghin","doi":"10.1088/1361-6471/acdaea","DOIUrl":"https://doi.org/10.1088/1361-6471/acdaea","url":null,"abstract":"\u0000 The quark-antiquark components of the U(3) lightest scalar meson nonet are investigated by considering the Nambu-Jona-Lasinio model with flavor-dependent coupling constants that were derived by considering (non-perturbative) gluon exchange. The strange quark effective mass ($M_s^*$) is varied such that the strangeness content of these scalar mesons can be analyzed further. The neutral states $S_0$, $S_8$ and $S_3$, are adopted as the most relevant quark-antiquark components respectively of the $sigma(500)$, $f_0(980)$ and $A_0^0(980)$ mesons. As a result, the mass hierarchy between states $S_0$ and $S_8$, and $K^*_0(700) - A_0(980)$ mesons, can be respectively inverted and corrected for quite low values of the strange quark constituent mass. Besides that, for some particular values of $M_s^*$, the masses of $sigma(500)$ and $f_0(980)$ can also be obtained by considering the mixing coupling constant $G_{08}$. However, the masses of all the nine mesons are not described simultaneously in a self-consistent procedure, and this goes along with the need of non-quark-antiquark states to completely describe their masses. A neutral-meson mixing matrix is defined and the leading mixing angle is found by fitting a correct value of the $sigma (500) -f_0 (980)$ mass difference. Two different estimates for the strengths of the mixings $A_0^0 to f_0$ and $f_0 to A_0^0$ are proposed, leading to somewhat different behaviors. Firstly, by assuming leading transitions to intermediary flavor eigenstates and secondly by considering a dynamical evolution. Results may be in good agreement with experimental values from BESS-III depending on the value of the strange quark effective mass.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2022-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42128858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Half-lives for proton emission and α decay within the deformed Gamow-like model","authors":"Qiong Xiao, Jun-Hao Cheng, Bin Wang, Yang-Yang Xu, Y. Zou, T. Yu","doi":"10.1088/1361-6471/acdfeb","DOIUrl":"https://doi.org/10.1088/1361-6471/acdfeb","url":null,"abstract":"\u0000 In the present work, α decay and proton emission half-lives are studied by the deformed Gamow-like model, which introduces the effects of the nucleus' deformation. The calculations show that it is necessary to consider the deformation in the calculation for nuclei far from the shell. Moreover, this model is used to predict the proton emission half-lives of the nuclei far from the shell more accurately. The calculations indicate that our deformed model follows the Geiger-Nuttall law. Furthermore, the deformed Gamow-like model is used to study the shell structure, and we find that the number of the next neutron shell is likely to be 152. This work may benefit future research on the search for superheavy nuclei and new proton radionuclides.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2022-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46048674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Technical design report for the endcap disc DIRC\u0000 *","authors":"F. Daví, W. Erni, B. Krusche, M. Steinacher, N. Walford, H. Liu, Z. Liu, Bo Liu, X. Shen, C. Wang, J. Zhao, M. Albrecht, T. Erlen, F. Feldbauer, M. Fink, V. Freudenreich, M. Fritsch, F. Heinsius, T. Held, T. Holtmann, I. Keshk, H. Koch, B. Kopf, M. Kuhlmann, M. Kümmel, S. Leiber, P. Musiol, A. Mustafa, M. Pelizäus, A. Pitka, G. Reicherz, M. Richter, C. Schnier, T. Schröder, S. Sersin, L. Sohl, C. Sowa, M. Steinke, T. Triffterer, U. Wiedner, R. Beck, C. Hammann, J. Hartmann, B. Ketzer, M. Kube, M. Rossbach, C. Schmidt, R. Schmitz, U. Thoma, M. Urban, A. Bianconi, M. Bragadireanu, D. Pantea, W. Czyżycki, M. Domagala, G. Filo, J. Jaworowski, M. Krawczyk, E. Lisowski, F. Lisowski, M. Michalk, J. Plazek, K. Korcyl, A. Kozela, P. Kulessa, P. Lebiedowicz, K. Pysz, W. Schäfer, A. Szczurek, T. Fiutowski, M. Idzik, B. Mindur, K. Swientek, J. Biernat, B. Kamys, S. Kistryn, G. Korcyl, W. Krzemień, A. Magiera, P. Moskal, W. Przygoda, Z. Rudy, P. Salabura, J. Smyrski, P. Strzempek, A. Wrońska, I. Augustin, R. Böhm, I. ","doi":"10.1088/1361-6471/abb6c1","DOIUrl":"https://doi.org/10.1088/1361-6471/abb6c1","url":null,"abstract":"\u0000 PANDA (anti-proton annihiliation at Darmstadt) is planned to be one of the four main experiments at the future international accelerator complex FAIR (Facility for Antiproton and Ion Research) in Darmstadt, Germany. It is going to address fundamental questions of hadron physics and quantum chromodynamics using cooled antiproton beams with a high intensity and and momenta between 1.5 and 15 GeV/c. PANDA is designed to reach a maximum luminosity of 2 × 1032 cm−2 s. Most of the physics programs require an excellent particle identification (PID). The PID of hadronic states at the forward endcap of the target spectrometer will be done by a fast and compact Cherenkov detector that uses the detection of internally reflected Cherenkov light (DIRC) principle. It is designed to cover the polar angle range from 5° to 22° and to provide a separation power for the separation of charged pions and kaons up to 3 standard deviations (s.d.) for particle momenta up to 4 GeV/c in order to cover the important particle phase space. This document describes the technical design and the expected performance of the novel PANDA disc DIRC detector that has not been used in any other high energy physics experiment before. The performance has been studied with Monte-Carlo simulations and various beam tests at DESY and CERN. The final design meets all PANDA requirements and guarantees sufficient safety margins.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41998522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vector meson photoproduction in UPCs with FoCal","authors":"A. Bylinkin, J. Nystrand, D. Takaki","doi":"10.1088/1361-6471/acc419","DOIUrl":"https://doi.org/10.1088/1361-6471/acc419","url":null,"abstract":"\u0000 We discuss the physics prospects of photon-induced measurements using the high-granularity FoCal detector to be installed at the ALICE experiment, covering the pseudorapidity interval 3.4 ≤ η ≤ 5.8. This new detector, scheduled to be in operation from Run 4, will explore the small Bjorken-x physics region in an unprecedented way. In this region the gluon saturation phenomenon is expected to be dominant. Combined with the rest of the ALICE subdetectors, including the zero degree calorimenters, FoCal will serve to reconstruct in a model-independent way the measured photoproduction cross sections for vectors mesons in a wide range of photon-target energies, down to x values of about 7 × 10-6 and 2 × 10-6 in ultra-peripheral photon–proton and photon–lead collisions, respectively.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2022-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49629459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dipole responses in γ−soft 124-134Xe in the spectroscopic energy region","authors":"H. Quliyev, E. Guliyev, A. A. Kuliev","doi":"10.1088/1361-6471/aca3c0","DOIUrl":"https://doi.org/10.1088/1361-6471/aca3c0","url":null,"abstract":"\u0000 This study aimed to systematically investigate the low-lying dipole states of even-even 124-134Xe isotopes using the quasi-particle random phase approximation (QRPA) method. Where in all the studied xenon isotopes, electric and magnetic dipole responses were clearly predicted. The calculations predict mainly a scissors mode, while the strength of weakly deformed 132, 134Xe was small compared to moderately deformed 124-130Xe isotopes, where electric dipole excitations make their own contributions as well. The obtained results are consistent with the available experimental data. Since it was not possible to experimentally determine the parity of dipole states here trougth comparison our results with experiment, we investigated the role of electric and magnetic dipole excitations in forming the spectrum. After comparing the obtained results with the experimentally derived ones, the natures of several observed spin- and parity-unknown excitations were determined.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44270232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microscopic calculation of the electromagnetic dipole strength for 239,243Pu isotopes","authors":"H. Yakut, E. Tabar, E. Kemah, G. Hoşgör","doi":"10.1088/1361-6471/aca3bf","DOIUrl":"https://doi.org/10.1088/1361-6471/aca3bf","url":null,"abstract":"\u0000 This work investigates the electric and magnetic dipole (E1 and M1) responses for 239,243Pu isotopes based on the quasiparticle phonon nuclear model (QPNM) by adding the residual interactions for addressing the violations of rotational, translational, and Galilean symmetries caused by the mean-field approach, for the first time. We focus on the E1 and M1 dipole strengths and photo-absorption cross sections up to 20 MeV, and the results reveal that the giant dipole resonance (GDR) best describes the experimental trend with a ratio of 95%. It appears that most of the E1 strength is found at Ex=8–20 MeV, but the total B(E1)↑ strength for the pygmy dipole resonance (PDR) at Ex=4–8 MeV accounts for some 1.83 e2fm2, which in turn corresponds to 2% of the Thomas–Reiche–Kuhn (TRK) sum rule. Furthermore, the resultant total B(M1)↑ value for the scissors mode strength below 4 MeV is 5.65 , which is lower than that of the Oslo data (10.1(15) ). However, the theoretically predicted scissors resonance structure with two peaks in the 1–3.5 MeV energy range exhibits a similar trend to that found in the Oslo data.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48485282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurement of excitation functions for \u0000 nat\u0000 Cu(α,x) reactions with detailed covariance analysis","authors":"Mahesh Choudhary, Aman Sharma, A. Gandhi, N. Singh, P. Dubey, Mahima Upadhyay, Utkarsha Mishra, Nitin Dubey, S. Dasgupta, J. Datta, K. Katovský, Ajay Kumar","doi":"10.1088/1361-6471/aca1d7","DOIUrl":"https://doi.org/10.1088/1361-6471/aca1d7","url":null,"abstract":"\u0000 The excitation functions of $^{66}$Ga, $^{67}$Ga, $^{65}$Zn and $^{64}$Cu radioisotopes produced via alpha-induced reaction on $^{nat}$Cu were measured using a stacked-foil activation method. The gamma-ray activity produced by the above-mentioned radionuclides was measured using the HPGe detector. The covariance analysis was performed to quantify the measured cross-section uncertainties as well as the correlation between different alpha energy cross sections. A covariance matrix and cross-sections for the $^{nat}$Cu($alpha$,x)$^{66}$Ga, $^{nat}$Cu($alpha$,x)$^{67}$Ga, $^{nat}$Cu($alpha$,x)$^{65}$Zn and $^{nat}$Cu($alpha$,x)$^{64}$Cu nuclear reactions in the projectile energy range of 15–37 MeV are reported in the present work. The measured reaction cross sections are compared with the existing experimental data and theoretically simulated results from the TALYS code.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2022-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42509527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}