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

{"title":"Lorentz violation in γ-pair production (e + e − → γ γ)","authors":"Alessio T B Celeste, Adriano M Santos","doi":"10.1088/1361-6471/ad2309","DOIUrl":"https://doi.org/10.1088/1361-6471/ad2309","url":null,"abstract":"In this paper, we investigate the production process of a photon pair in a regime of quantum electrodynamics, considering the presence of a constant four-vector that defines a privileged direction in spacetime, resulting in Lorentz symmetry violation. We explore Lorentz violation in the context of vectorial nonminimal coupling, where we analyze the modifications introduced by this coupling in the scattering amplitude at the vertex. Moreover, we delve into Lorentz violation with axial-like nonminimal coupling. Both analyses are conducted by examining the constant four-vector of both time-like and space-like types.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":"4 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140008654","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":"Feasibility study to characterize the production of antineutrons in high energy pp collisions through charge exchange interactions","authors":"F Lugo-Porras, D M Gomez-Coral, A Menchaca-Rocha","doi":"10.1088/1361-6471/ad1dc1","DOIUrl":"https://doi.org/10.1088/1361-6471/ad1dc1","url":null,"abstract":"Simulations to evaluate the feasibility of antineutron identification and kinematic characterization via the hadronic charge exchange (CEX) interaction <inline-formula>\u0000<tex-math>\u0000<?CDATA $n,+,bar{n},to ,p,+,bar{p}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mi>n</mml:mi><mml:mspace width=\"0.25em\"></mml:mspace><mml:mo>+</mml:mo><mml:mspace width=\"0.25em\"></mml:mspace><mml:mover accent=\"true\"><mml:mi>n</mml:mi><mml:mo>¯</mml:mo></mml:mover><mml:mspace width=\"0.25em\"></mml:mspace><mml:mo>→</mml:mo><mml:mspace width=\"0.25em\"></mml:mspace><mml:mi>p</mml:mi><mml:mspace width=\"0.25em\"></mml:mspace><mml:mo>+</mml:mo><mml:mspace width=\"0.25em\"></mml:mspace><mml:mover accent=\"true\"><mml:mi>p</mml:mi><mml:mo>¯</mml:mo></mml:mover></mml:math>\u0000<inline-graphic xlink:href=\"jpgad1dc1ieqn1.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> are reported. The target neutrons are those composing the silicon nuclei of which inner tracking devices present in the Large Hadron Collider experiments ALICE, ATLAS, and CMS. Simulations of <italic toggle=\"yes\">pp</italic> collisions in PYTHIA were carried out at different energies to investigate <inline-formula>\u0000<tex-math>\u0000<?CDATA $bar{n}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mover accent=\"true\"><mml:mrow><mml:mi>n</mml:mi></mml:mrow><mml:mrow><mml:mo>¯</mml:mo></mml:mrow></mml:mover></mml:math>\u0000<inline-graphic xlink:href=\"jpgad1dc1ieqn2.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> production and energy spectra. These simulations produced a decreasing power-law <inline-formula>\u0000<tex-math>\u0000<?CDATA $bar{n}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mover accent=\"true\"><mml:mrow><mml:mi>n</mml:mi></mml:mrow><mml:mrow><mml:mo>¯</mml:mo></mml:mrow></mml:mover></mml:math>\u0000<inline-graphic xlink:href=\"jpgad1dc1ieqn3.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> energy spectra. Then, two types of GEANT4 simulations were performed, placing an <inline-formula>\u0000<tex-math>\u0000<?CDATA $bar{n}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mover accent=\"true\"><mml:mrow><mml:mi>n</mml:mi></mml:mrow><mml:mrow><mml:mo>¯</mml:mo></mml:mrow></mml:mover></mml:math>\u0000<inline-graphic xlink:href=\"jpgad1dc1ieqn4.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> point source at the ALICE primary vertex, as a working example. In the first simulation, the kinetic energy <italic toggle=\"yes\">E</italic>\u0000<sub>\u0000<italic toggle=\"yes\">k</italic>\u0000</sub> was kept at an arbitrary (1 GeV) fix value to develop an <inline-formula>\u0000<tex-math>\u0000<?CDATA $bar{n}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mover accent=\"true\"><mml:mrow><mml:mi>n</mml:mi></mml:mrow><mml:mrow><mml:mo>¯</mml:mo></mml:mrow></mml:mover></mml:math>\u0000<inline-graphic xlink:href=\"jpgad1dc1ieqn5.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> identification and kinematics reconstruction protocol. The second GEANT4 simulation used the resulting PYTHIA at <inline-formula>\u0000<tex-math>\u0000<?CDATA $sqrt{{s}_{{pp}}},=,13$?>","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":"153 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139751408","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":"Spectroscopic analysis of hidden-charm pentaquarks","authors":"Ankush Sharma, Alka Upadhyay","doi":"10.1088/1361-6471/ad1eb8","DOIUrl":"https://doi.org/10.1088/1361-6471/ad1eb8","url":null,"abstract":"In this work, the multiquark approach is used to analyze the spectroscopy of hidden-charm pentaquark states, motivated by recent discoveries at the LHCb collaboration. Using the SU(3) flavor representation, pentaquarks having <italic toggle=\"yes\">J</italic>\u0000^{\u0000<italic toggle=\"yes\">P</italic>\u0000} = 5/2⁻ are arranged into 10 (decuplet) of the SU(3) flavor multiplets. The masses of pentaquarks are calculated using the extension of the Gursey–Radicati mass formula and the effective mass scheme. Also, we calculated the magnetic moments of the hidden-charm pentaquarks using the effective mass and shielded charge technique. Further, we suggested the possible production modes for <italic toggle=\"yes\">J</italic>\u0000^{\u0000<italic toggle=\"yes\">P</italic>\u0000} = 5/2⁻ pentaquarks from the decay of bottom baryons, which consist of pentaquark states as intermediate states. Our results for masses demonstrate reasonable agreement with the available data and our analysis for both masses and magnetic moments may be useful for future experimental studies.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":"15 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139773262","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":"Alternative 3-3-1 models with exotic electric charges","authors":"Eduard Suarez, Richard H Benavides, Yithsbey Giraldo, William A Ponce, Eduardo Rojas","doi":"10.1088/1361-6471/ad1e21","DOIUrl":"https://doi.org/10.1088/1361-6471/ad1e21","url":null,"abstract":"We report the most general classification of 3-3-1 models with <inline-formula>\u0000<tex-math>\u0000<?CDATA $beta =sqrt{3}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mi>β</mml:mi><mml:mo>=</mml:mo><mml:msqrt><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msqrt></mml:math>\u0000<inline-graphic xlink:href=\"jpgad1e21ieqn1.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>. We found several solutions where anomaly cancellation occurs among fermions of different families. These solutions are particularly interesting as they generate non-universal heavy neutral vector bosons. Non-universality in the standard model fermion charges under an additional gauge group generates charged lepton flavor violation and flavor changing neutral currents; we discuss under what conditions the new models can evade constraints coming from these processes. In addition, we also report the <italic toggle=\"yes\">Large Hadron Collider</italic>~(LHC) constraints.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":"52 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139751536","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":"Pairing effects on pure rotational energy of nuclei","authors":"K Abe, H Nakada","doi":"10.1088/1361-6471/ad1a77","DOIUrl":"https://doi.org/10.1088/1361-6471/ad1a77","url":null,"abstract":"By applying the angular-momentum projection to the self-consistent axial mean-field solutions with the semi-realistic effective Hamiltonian M3Y-P6, the pairing effects on the pure rotational energy of nuclei, i.e. the rotational energy at a fixed intrinsic state, have been investigated. While it was shown at the Hartree–Fock (HF) level that the individual terms of the Hamiltonian contribute to the rotational energy with ratios insensitive to nuclides except for light or weakly-deformed nuclei, the pair correlations significantly change the contributions, even for the well-deformed heavy nuclei. The contribution of the interaction to the rotational energy is found to correlate well with the degree of proximity between nucleons, which is measured via the expectation value that two nucleons exist at the same position. While the nucleons slightly spread as the angular momentum increases at the HF level, accounting for the positive (negative) contribution of the attractive (repulsive) components of the interaction, the pair correlations reduce or invert the effect.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":"256 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139751481","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":"Searches for baryon number violation in neutrino experiments: a white paper","authors":"P S B Dev, L W Koerner, S Saad, S Antusch, M Askins, K S Babu, J L Barrow, J Chakrabortty, A de Gouvêa, Z Djurcic, S Girmohanta, I Gogoladze, M C Goodman, A Higuera, D Kalra, G Karagiorgi, E Kearns, V A Kudryavtsev, T Kutter, M Malinský, D A Martinez Caicedo, R N Mohapatra, P Nath, S Nussinov, J P Ochoa-Ricoux, V Pec, A Rafique, J Rodriguez Rondon, R Shrock, H W Sobel, T Stokes, M Strait, R Svoboda, S Syritsyn, V Takhistov, Y-T Tsai, R A Wendell, Y-L Zhou","doi":"10.1088/1361-6471/ad1658","DOIUrl":"https://doi.org/10.1088/1361-6471/ad1658","url":null,"abstract":"Baryon number conservation is not guaranteed by any fundamental symmetry within the standard model, and therefore has been a subject of experimental and theoretical scrutiny for decades. So far, no evidence for baryon number violation has been observed. Large underground detectors have long been used for both neutrino detection and searches for baryon number violating processes. The next generation of large neutrino detectors will seek to improve upon the limits set by past and current experiments and will cover a range of lifetimes predicted by several Grand Unified Theories. In this White Paper, we summarize theoretical motivations and experimental aspects of searches for baryon number violation in neutrino experiments.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":"65 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139751480","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":"Daily and annual modulation rate of low mass dark matter in silicon detectors","authors":"Abolfazl Dinmohammadi, Matti Heikinheimo, Nader Mirabolfathi, Kai Nordlund, Hossein Safari, Sebastian Sassi, Kimmo Tuominen","doi":"10.1088/1361-6471/ad1a76","DOIUrl":"https://doi.org/10.1088/1361-6471/ad1a76","url":null,"abstract":"Low-threshold solid-state detectors with single electron excitation sensitivity can probe nuclear recoil energies in the sub-100 eV range, coinciding with the typical threshold displacement energies in the detector material. We investigate the daily and annual modulation of the observable event rate for dark matter mass ranging from 0.2 to 5 GeV/c² in a silicon detector, considering the energy threshold and the direction of the nuclear recoil. The data for the energy threshold is obtained from a molecular dynamics simulation. It is shown that the directional dependence of the threshold energy and the motion of the laboratory result in the modulation of the interaction event rate. We demonstrate silicon’s average annual interaction rate is more considerable than germanium for low-mass dark matter. However, their event rates take a similar trend in large dark matter masses. Thus, silicon can be a reliable target to discriminate low-mass dark matter from backgrounds. We also find 8 h and 12h periodicities in the time series of event rates for silicon detectors due to the 45-degree symmetry in the silicon crystal structure.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":"5 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139751414","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":"Fate of false vacuum in non-perturbative regimes","authors":"Marco Frasca, Anish Ghoshal, Nobuchika Okada","doi":"10.1088/1361-6471/ad170e","DOIUrl":"https://doi.org/10.1088/1361-6471/ad170e","url":null,"abstract":"We use some exact results in scalar field theory to revise the analysis by Coleman and Callan about false vacuum decay and propose a simple non-perturbative formalism. We introduce an exact Green’s function which incorporates non-perturbative corrections in the strong coupling regimes of the theory. The solution of the scalar field theory involves the Jacobi elliptical function and has been used to calculate the effective potential for any arbitrary coupling values. We demonstrate the use of this formalism in a simple <italic toggle=\"yes\">λ</italic>\u0000<italic toggle=\"yes\">ϕ</italic>\u0000⁴ theory, and show that the effective potential exhibits a false minimum at the origin. We then calculate the false vacuum decay rate in the thin wall approximation, and suggest simple analytic formulae that may be useful for the analysis for the first-order phase transition beyond the perturbative regime. In our methodology, we show that the standard results obtained in perturbation theory are reproduced by making the coupling values very small.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":"98 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139509467","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":"Influence of hyperon–hyperon interaction on the properties of neutron stars","authors":"R M Aguirre","doi":"10.1088/1361-6471/ad15e6","DOIUrl":"https://doi.org/10.1088/1361-6471/ad15e6","url":null,"abstract":"The properties of neutron stars are studied in a composite model of the strong interaction. In the regime of low to medium baryonic densities a covariant hadronic model is adopted which includes an exclusive channel for the hyperon–hyperon interaction mediated by hidden strangeness mesons, which in turn couple to other mesons through polynomial vertices. The new coupling constants are subject to phenomenological constraints. The presence of free quarks in the core of the star is considered by using the Nambu–Jona Lasinio model supplemented with a vector interaction. The deconfinement process is described by a continuous coexistence of phases. Several structure parameters of neutron stars, such as mass-radius relation, moment of inertia, tidal deformability, and the propagation of nonradial f and g-modes within the relativistic Cowling approximation are studied. The predictions of the model are in good agreement with recent observational data, in particular the maximum inertial mass is greater than the observational lower limit of two solar masses.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":"59 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139509619","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":"New physics hints from τ scalar interactions and (g − 2) e,μ","authors":"Francisco J Botella, Fernando Cornet-Gomez, Carlos Miró, Miguel Nebot","doi":"10.1088/1361-6471/ad0ffa","DOIUrl":"https://doi.org/10.1088/1361-6471/ad0ffa","url":null,"abstract":"We consider a flavour conserving two Higgs doublet model that consists of a type I (or X) quark sector and a generalized lepton sector where the Yukawa couplings of the charged leptons to the new scalars are not proportional to the lepton masses. The model, previously proposed to solve both muon and electron <italic toggle=\"yes\">g</italic> − 2 anomalies simultaneously, is also capable to accommodate the ATLAS excess in <italic toggle=\"yes\">pp</italic> → <italic toggle=\"yes\">S</italic> → <italic toggle=\"yes\">τ</italic>\u0000⁺\u0000<italic toggle=\"yes\">τ</italic>\u0000⁻ with gluon–gluon fusion production in the invariant mass range [0.2; 0.6] TeV, including all relevant low and high energy constraints. The excess is reproduced taking into account the new contributions from the scalar H, the pseudoscalar A, or both. In particular, detailed numerical analyses favoured the solution with a significant hierarchy among the vevs of the two Higgs doublets, <italic toggle=\"yes\">t</italic>\u0000_{\u0000<italic toggle=\"yes\">β</italic>\u0000} ∼ 10, and light neutral scalars satisfying <italic toggle=\"yes\">m</italic>\u0000_A &gt; <italic toggle=\"yes\">m</italic>\u0000_H with sizable couplings to <italic toggle=\"yes\">τ</italic> leptons. In this region of the parameter space, the muon <italic toggle=\"yes\">g</italic> − 2 anomaly receives one and two-loop (Barr-Zee) contributions of similar size, while the electron anomaly is explained at two loops. An analogous ATLAS excess in <italic toggle=\"yes\">b</italic>-associated production and the CMS excess in ditop production are also studied. Further New Physics prospects concerning the anomalous magnetic moment of the <italic toggle=\"yes\">τ</italic> lepton and the implications of the CDF <italic toggle=\"yes\">M</italic>\u0000_{\u0000<italic toggle=\"yes\">W</italic>\u0000} measurement on the final results are discussed.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":"8 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139093528","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}