The European Physical Journal C最新文献_第10页

CP asymmetries of (t rightarrow c gamma ) and (t rightarrow cg) decays in the aligned two-Higgs-doublet model

IF 4.2 2区物理与天体物理

The European Physical Journal C Pub Date : 2025-03-13 DOI: 10.1140/epjc/s10052-025-13965-w

Fang-Min Cai, Rui-Lin Fan, Xin-Qiang Li, Ya-Dong Yang

{"title":"CP asymmetries of (t rightarrow c gamma ) and (t rightarrow cg) decays in the aligned two-Higgs-doublet model","authors":"Fang-Min Cai, Rui-Lin Fan, Xin-Qiang Li, Ya-Dong Yang","doi":"10.1140/epjc/s10052-025-13965-w","DOIUrl":"10.1140/epjc/s10052-025-13965-w","url":null,"abstract":"<div>We study the CP asymmetries of the rare top-quark decays (t rightarrow c gamma ) and (t rightarrow cg) in the aligned two-Higgs-doublet model (A2HDM), which is generically characterized by new sources of CP violation beyond the Standard Model (SM). Specifically, the branching ratios and CP asymmetries of these rare top-quark decays are explicitly formulated, with an emphasis on the origins of weak and strong phases in the A2HDM. Taking into account the most relevant constraints on this model, we evaluate the variations of these observables with respect to the model parameters. It is found that the branching ratios of (t rightarrow c gamma ) and (t rightarrow cg) decays can maximally reach up to (1.47times 10^{-10}) and (4.86times 10^{-9}) respectively, which are about four and three orders of magnitude higher than the corresponding SM predictions. While the branching ratios are almost independent of the relative phase (varphi ) between the two alignment parameters (varsigma _u) and (varsigma _d) within the allowed parameter space, the CP asymmetries are found to be very sensitive to (varphi .) When the two alignment parameters are complex with a non-zero (varphi ) varied within the range ([50^circ ,150^circ ],) the magnitudes of the CP asymmetries can be significantly enhanced relative to both the SM and the real case. In particular, the maximum absolute values of the CP asymmetries can even reach up to ({mathcal {O}}(1)) for these two decay modes, in the range (varphi in [70^circ ,100^circ ].) These interesting observations could be utilized to discriminate the SM and the different scenarios of the A2HDM.</div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 3","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-13965-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143602365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Revealing mysteries in gamma-ray bursts: the role of gluon condensation

IF 4.2 2区物理与天体物理

The European Physical Journal C Pub Date : 2025-03-13 DOI: 10.1140/epjc/s10052-025-13933-4

Wei Zhu, Xu-Rong Chen, Yu-Chen Tang

引用次数: 0

Neutral-current background induced by atmospheric neutrinos at large liquid-scintillator detectors: III. Comprehensive prediction for low energy neutrinos

IF 4.2 2区物理与天体物理

The European Physical Journal C Pub Date : 2025-03-13 DOI: 10.1140/epjc/s10052-025-14009-z

Jie Cheng, Min Li, Yu-Feng Li, Gao-Song Li, Hao-Qi Lu, Liang-Jian Wen

{"title":"Neutral-current background induced by atmospheric neutrinos at large liquid-scintillator detectors: III. Comprehensive prediction for low energy neutrinos","authors":"Jie Cheng, Min Li, Yu-Feng Li, Gao-Song Li, Hao-Qi Lu, Liang-Jian Wen","doi":"10.1140/epjc/s10052-025-14009-z","DOIUrl":"10.1140/epjc/s10052-025-14009-z","url":null,"abstract":"<div>Atmospheric neutrinos play a vital role in generating irreducible backgrounds in liquid-scintillator (LS) detectors via their neutral-current (NC) interactions with 12C nuclei. These interactions may affect a wide range of research areas from the MeV to GeV energy range, such as the reactor and geo neutrinos, diffuse supernova neutrino background (DSNB), dark matter, and nucleon decay searches. In this work, we extend our preceding paper (Cheng et al. in Phys. Rev. D 103(5):053001, 2021), by conducting a first-time systematic exploration of NC backgrounds as low as the MeV region of reactor and geo neutrinos. We utilize up-to-date neutrino generator models from GENIE and NuWro, a TALYS-based nuclear deexcitation package and a GEANT4-based detector simulation toolkit for our complete calculation. Our primary focus is to predict the NC background for experimental searches of inverse-beta-decay signals below the 100 MeV visible energy. In order to have deeper understanding of the characteristics of atmospheric neutrino NC interactions in LS, we investigate the model dependence of NC background predictions by using various data-driven models, including the initial neutrino-nucleon interactions, nuclear ground-state structure, final-state interactions, nuclear deexcitation processes, and secondary interactions of final-state particles.\u0000</div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 3","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14009-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143612129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Constraint on Lorentz invariance violation for spectral lag transition in GRB 160625B using profile likelihood

IF 4.2 2区物理与天体物理

The European Physical Journal C Pub Date : 2025-03-13 DOI: 10.1140/epjc/s10052-025-14016-0

Shantanu Desai, Shalini Ganguly

{"title":"Constraint on Lorentz invariance violation for spectral lag transition in GRB 160625B using profile likelihood","authors":"Shantanu Desai, Shalini Ganguly","doi":"10.1140/epjc/s10052-025-14016-0","DOIUrl":"10.1140/epjc/s10052-025-14016-0","url":null,"abstract":"<div>We reanalyze the spectral lag data for GRB 160625B using frequentist inference in order to constrain the energy scale ((E_{QG})) of Lorentz Invariance Violation (LIV). For this purpose, we use profile likelihood to deal with the astrophysical nuisance parameters. This is in contrast to Bayesian inference implemented in previous works, where marginalization was carried out over the nuisance parameters. We show that with profile likelihood, we do not find a global minimum for (chi ^2) as a function of (E_{QG}) below the Planck scale for both linear and quadratic models of LIV, whereas bounded credible intervals were previously obtained using Bayesian inference. Therefore, we can set one-sided lower limits in a straightforward manner. We find that (E_{QG} ge 2.55 times 10^{16}) GeV and (E_{QG} ge 1.85 times 10^7) GeV at 95% c.l., for linear and quadratic LIV, respectively. Therefore, this is the first proof-of-principles application of profile likelihood method to the analysis of GRB spectral lag data to constrain LIV.\u0000</div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 3","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14016-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143612132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Implications of DES 5YR SNe Dataset for (Lambda )CDM

IF 4.2 2区物理与天体物理

The European Physical Journal C Pub Date : 2025-03-13 DOI: 10.1140/epjc/s10052-025-13995-4

Eoin Ó Colgáin, Saeed Pourojaghi, M. M. Sheikh-Jabbari

{"title":"Implications of DES 5YR SNe Dataset for (Lambda )CDM","authors":"Eoin Ó Colgáin, Saeed Pourojaghi, M. M. Sheikh-Jabbari","doi":"10.1140/epjc/s10052-025-13995-4","DOIUrl":"10.1140/epjc/s10052-025-13995-4","url":null,"abstract":"<div>Dark Energy Survey 5-year supernovae data (DES 5YR SNe) in conjunction with Planck CMB and Dark Energy Spectroscopic Instrument (DESI) BAO data has detected a strong dynamical dark energy (DE) deviation from the (Lambda )CDM model. Here we shift the focus of DES data to the pressureless matter sector in the (Lambda )CDM model by studying the matter density parameter (Omega _m). Employing primarily frequentist profile likelihoods, supported by complementary Bayesian methods, we demonstrate that (Omega _m) increases with effective redshift in the DES data up to a point that there is a (2.5 sigma ) discrepancy with Planck. We relax the traditional (Omega _m le 1) prior to demonstrate negative DE densities (Omega _m > 1) at the highest effective redshift probed. Nevertheless, the largest discrepancy with Planck occurs for profile likelihoods and posteriors peaked at (Omega _m < 1) in the traditional (Lambda )CDM regime. Our findings corroborate earlier observations in Pantheon and Pantheon+ datasets with an independent SNe dataset with a higher effective redshift. In an appendix, we confirm that curvature (Omega _k) decreases with effective redshift disfavouring a flat Universe in higher redshift DES SNe at (> 3 sigma ). Our choice of (Omega _k) prior leads to an underestimation of the tension with a flat Universe.</div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 3","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-13995-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143602361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Scalar fields with impurities in arbitrary dimensions: first-order framework and exact solutions

IF 4.2 2区物理与天体物理

The European Physical Journal C Pub Date : 2025-03-12 DOI: 10.1140/epjc/s10052-025-14004-4

D. Bazeia, M. A. Marques, R. Menezes

引用次数: 0

Cosmic slowing down of acceleration with the Chaplygin–Jacobi gas as a dark fluid?

IF 4.2 2区物理与天体物理

The European Physical Journal C Pub Date : 2025-03-12 DOI: 10.1140/epjc/s10052-025-13996-3

J. A. S. Fortunato, W. S. Hipólito-Ricaldi, N. Videla, J. R. Villanueva

{"title":"Cosmic slowing down of acceleration with the Chaplygin–Jacobi gas as a dark fluid?","authors":"J. A. S. Fortunato, W. S. Hipólito-Ricaldi, N. Videla, J. R. Villanueva","doi":"10.1140/epjc/s10052-025-13996-3","DOIUrl":"10.1140/epjc/s10052-025-13996-3","url":null,"abstract":"<div>A particular generalization of the Chaplygin inflationary model, using the formalism of Hamilton–Jacobi and elliptic functions, results in a more general non-linear Chaplygin-type equation of state (Chaplygin–Jacobi model). We investigate the implementation of this model as a dark energy (DE) fluid to explain the recent acceleration of the universe. Unlike (Lambda )CDM and other Chaplygin-like fluids, where the final fate of the universe is an eternal de Sitter (dS) phase, the dynamics of this model allows for the possibility of a decelerating phase in the future, following the current accelerating phase. In other words, a transient acceleration arises, accounting for the recently claimed slowing down phenomenon. This Chaplygin–Jacobi model shows important differences compared to the standard and generalized Chaplygin gas models. Additionally, we perform a Markov Chain Monte Carlo (MCMC) analysis using several datasets, including type Ia supernovae (SNIa), cosmic chronometers (CC), fast radio bursts (FRBs), and Baryon acoustic oscillations (BAO) to examine the observational viability of the model. Our results indicate that, although a transient phase of accelerated expansion is supported by current observations in the context of the Chaplygin–Jacobi model, this model is strongly disfavored in comparison with (Lambda )CDM.</div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 3","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-13996-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143594751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On the momentum space structure of the quark propagator

IF 4.2 2区物理与天体物理

The European Physical Journal C Pub Date : 2025-03-12 DOI: 10.1140/epjc/s10052-025-13984-7

O. Oliveira, T. Frederico, W. de Paula

引用次数: 0

Compact stellar models with quasi-local anisotropy

IF 4.2 2区物理与天体物理

The European Physical Journal C Pub Date : 2025-03-12 DOI: 10.1140/epjc/s10052-025-13946-z

Shyam Das, Bikash Chandra Paul, Iftikar Hossain Sardar, Shyamal Kumar Pal

引用次数: 0

Normal mode analysis within a mutilated relaxation time approximation