Physics Letters B最新文献

{"title":"Higher order flow coefficients – a messenger of QCD medium formed in heavy-ion collisions at the Large Hadron Collider","authors":"Suraj Prasad ,&nbsp;Aswathy Menon Kavumpadikkal Radhakrishnan ,&nbsp;Raghunath Sahoo ,&nbsp;Neelkamal Mallick","doi":"10.1016/j.physletb.2025.139753","DOIUrl":"10.1016/j.physletb.2025.139753","url":null,"abstract":"<div><div>Anisotropic flow and fluctuations are sensitive observables of the initial state effects in heavy ion collisions and are characterized by the medium properties and final state interactions. Using event-shape observables, one can constrain the probability distributions of anisotropic flow coefficients, thus reducing the linear and nonlinear contributions in the measured higher-order harmonics. In this paper, we use transverse spherocity as an event shape observable to study the flow coefficients and elliptic flow fluctuations. Transverse spherocity is found to have a strong correlation with elliptic flow and its fluctuations. We exploit this feature of transverse spherocity to remove the contribution to elliptic flow from higher-order harmonics. The study is performed in Pb–Pb collisions at <span><math><msqrt><mrow><msub><mrow><mi>s</mi></mrow><mrow><mi>NN</mi></mrow></msub></mrow></msqrt><mo>=</mo><mn>5.02</mn></math></span> TeV using a multi-phase transport model. The multi-particle Q-cumulant method estimates the anisotropic flow coefficients, which reduces the non-flow contributions. We observe a stronger system response to the flow coefficients for the events with smaller values of elliptic flow.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"868 ","pages":"Article 139753"},"PeriodicalIF":4.3,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144714341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 the W boson decay branching fraction ratio B(W→cq)/B(W→qq¯′) in proton-proton collisions at s=13TeV","authors":"","doi":"10.1016/j.physletb.2025.139754","DOIUrl":"10.1016/j.physletb.2025.139754","url":null,"abstract":"<div><div>The most precise measurement to date of the <figure><img></figure> boson hadronic decay branching fraction ratio <figure><img></figure> is presented. The measurement is based on a sample of proton-proton collision data from the CERN LHC collected by the CMS experiment at a center-of-mass energy of 13 TeV in 2016–2018 with an integrated luminosity of <span><math><mn>138</mn><mrow><mspace></mspace><msup><mrow><mtext>fb</mtext></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>. The large cross section of top quark-antiquark production at the LHC offers a sizable high-purity sample of <figure><img></figure> bosons suitable for this measurement. Events with one charged lepton (electron or muon) and at least four jets, two tagged as bottom quark jets, are analyzed. Charm jets are tagged using the presence of a muon inside the jet. The result, <figure><img></figure>, is consistent with the standard model prediction and is twice as precise as the current world-average value.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"868 ","pages":"Article 139754"},"PeriodicalIF":4.3,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144714340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"An investigation of a varying G through Strong Lensing and SNe Ia observations","authors":"R.F.L. Holanda ,&nbsp;Marcelo Ferreira ,&nbsp;Javier E. Gonzalez","doi":"10.1016/j.physletb.2025.139756","DOIUrl":"10.1016/j.physletb.2025.139756","url":null,"abstract":"<div><div>In this paper, we analyze the potential variation of the gravitational constant <em>G</em> using data from strong gravitational lensing systems and Type Ia supernovae. Testing <span><math><mi>G</mi><mo>(</mo><mi>z</mi><mo>)</mo></math></span> parameterizations where <span><math><mi>G</mi><mo>(</mo><mi>z</mi><mo>)</mo><mo>=</mo><msub><mrow><mi>G</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>(</mo><mn>1</mn><mo>+</mo><msub><mrow><mi>G</mi></mrow><mrow><mn>1</mn></mrow></msub><mi>z</mi><mo>)</mo></math></span> and <span><math><mi>G</mi><mo>(</mo><mi>z</mi><mo>)</mo><mo>=</mo><msub><mrow><mi>G</mi></mrow><mrow><mn>0</mn></mrow></msub><msup><mrow><mo>(</mo><mn>1</mn><mo>+</mo><mi>z</mi><mo>)</mo></mrow><mrow><msub><mrow><mi>G</mi></mrow><mrow><mn>1</mn></mrow></msub></mrow></msup></math></span>, we also account for the influence of <em>G</em> on the luminosity of SNe Ia through the Chandrasekhar mass-luminosity relation. Only the flat universe hypothesis is considered. Constraints from 158 lensing systems and the Pantheon+ sample show no significant evidence of <em>G</em> variation. However, although the results are compatible with no variation, the errors are not yet sufficiently restrictive to rule out any variation of <em>G</em> with high statistical confidence. This study highlights the viability of using combined astrophysical data to probe variations in fundamental constants, suggesting that future surveys could refine these constraints.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"868 ","pages":"Article 139756"},"PeriodicalIF":4.5,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144722371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Search for absorption of light fermionic dark matter by electron target in xenon dark matter detector","authors":"X.P. Geng ,&nbsp;B. Zhong ,&nbsp;Z.H. Zhang","doi":"10.1016/j.physletb.2025.139747","DOIUrl":"10.1016/j.physletb.2025.139747","url":null,"abstract":"<div><div>A search for the absorption of light fermionic dark matter (DM) by electron target in xenon induced by vector (V) and axial-vector (A) operators is performed using the 1.16 tonne⋅year XENONnT electronic recoil data. With no significant signal observed, the one-sided 90% confidence level constraints on the effective coupling between fermionic DM and the electron (<span><math><msub><mrow><mi>σ</mi></mrow><mrow><mi>e</mi></mrow></msub><msub><mrow><mi>v</mi></mrow><mrow><mi>χ</mi></mrow></msub></math></span>) for DM mass <span><math><msub><mrow><mi>m</mi></mrow><mrow><mi>χ</mi></mrow></msub></math></span> ranging from 2 to 180 keV with both V and A operators are derived as results. We present the most stringent constraint for <span><math><msub><mrow><mi>m</mi></mrow><mrow><mi>χ</mi></mrow></msub></math></span> ranging from 14 to 93 keV (9 to 60 keV) with V (A) operator, establishing them as the strongest DM direct detection experiment constraints for <span><math><msub><mrow><mi>m</mi></mrow><mrow><mi>χ</mi></mrow></msub></math></span> ranging from 2 to 180 keV, with the XENON1T hint excluded.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"868 ","pages":"Article 139747"},"PeriodicalIF":4.3,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144714339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Emerging photon jets in the hadronic calorimeter: A novel signature of neutral long-lived particles at the LHC","authors":"Jinheung Kim ,&nbsp;Dongjoo Kim ,&nbsp;Soojin Lee ,&nbsp;Jeonghyeon Song","doi":"10.1016/j.physletb.2025.139759","DOIUrl":"10.1016/j.physletb.2025.139759","url":null,"abstract":"<div><div>We propose a novel collider signature for neutral long-lived particles (LLPs): the emerging photon jet in the hadronic calorimeter (HCAL). This signature arises when a neutral LLP decays into photons within the HCAL, producing an electromagnetic shower without associated charged tracks or energy deposits in the electromagnetic calorimeter (ECAL). To demonstrate the viability of this approach, we consider the fermiophobic Higgs boson <span><math><msub><mrow><mi>h</mi></mrow><mrow><mi>f</mi></mrow></msub></math></span> in the Type-I two-Higgs-doublet model as a representative scenario. In the ultralight regime (<span><math><msub><mrow><mi>m</mi></mrow><mrow><msub><mrow><mi>h</mi></mrow><mrow><mi>f</mi></mrow></msub></mrow></msub><mo>&lt;</mo><mn>1</mn></math></span> GeV), <span><math><msub><mrow><mi>h</mi></mrow><mrow><mi>f</mi></mrow></msub></math></span> decays exclusively into a photon pair via loop-induced processes, resulting in a suppressed width and consequently a long lifetime. Focusing on the golden channel <span><math><mi>p</mi><mi>p</mi><mo>→</mo><msup><mrow><mi>H</mi></mrow><mrow><mo>±</mo></mrow></msup><msub><mrow><mi>h</mi></mrow><mrow><mi>f</mi></mrow></msub><mo>→</mo><msup><mrow><mi>W</mi></mrow><mrow><mo>±</mo></mrow></msup><msub><mrow><mi>h</mi></mrow><mrow><mi>f</mi></mrow></msub><msub><mrow><mi>h</mi></mrow><mrow><mi>f</mi></mrow></msub></math></span>, we analyze the exotic final state in which one <span><math><msub><mrow><mi>h</mi></mrow><mrow><mi>f</mi></mrow></msub></math></span> decays in the ECAL and appears as a highly collimated photon jet (reconstructed as a single photon), while the other decays within the HCAL, producing an emerging photon jet. Through a detailed signal-to-background analysis incorporating realistic detector effects via fast simulation, we demonstrate that this signature achieves discovery-level sensitivity at the HL-LHC across a broad region of parameter space consistent with theoretical and experimental constraints. While our study focuses on the fermiophobic Higgs, the emerging photon jet in the HCAL constitutes a broadly applicable and previously unexplored strategy for detecting neutral LLPs decaying into photons, opening a new avenue in LLP searches at colliders.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"868 ","pages":"Article 139759"},"PeriodicalIF":4.3,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144694497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Suppression of elliptic anisotropy inside jets: A new perspective for jet quenching","authors":"Meng-Quan Yang ,&nbsp;Wei-Xi Kong ,&nbsp;Peng Ru ,&nbsp;Ben-Wei Zhang","doi":"10.1016/j.physletb.2025.139746","DOIUrl":"10.1016/j.physletb.2025.139746","url":null,"abstract":"<div><div>Particle azimuthal anisotropies inside jets, defined within the momentum plane perpendicular to the jet axis, carry the information of the QCD cascade process for jet formation. In this work, we propose to measure the medium-induced modifications of the elliptic anisotropy inside jets in relativistic heavy-ion collisions to provide novel insight into the jet quenching phenomenon. By simulating the jet propagation in the hot and dense nuclear medium with a Linear Boltzmann Transport model, we observe a de-correlation in the two-particle azimuthal angular distribution for inclusive jet production in AA collisions relative to that in <em>pp</em> collisions, which results in significant suppression of the in-jet elliptic anisotropy coefficient <span><math><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>. This phenomenon arises from the stochastic and strong interactions with the thermal QGP medium undergone by the jet particles. Furthermore, the nuclear modifications of the in-jet <span><math><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> are found to be sensitive to the medium properties in the model study, which provide a potential probe for the jet tomography of nuclear matter.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"868 ","pages":"Article 139746"},"PeriodicalIF":4.3,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144694496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Impact of evolving dark energy on the search for primordial gravitational waves","authors":"Hao Wang ,&nbsp;Gen Ye ,&nbsp;Yun-Song Piao","doi":"10.1016/j.physletb.2025.139744","DOIUrl":"10.1016/j.physletb.2025.139744","url":null,"abstract":"<div><div>Recent observational data have shown at <span><math><mo>≳</mo><mn>3</mn><mi>σ</mi></math></span> significance level that the dark energy (DE), responsible for the current accelerated expansion of our universe, is evolving. In this Letter, using the BICEP/Keck cosmic microwave background (CMB) B-mode polarization data, as well as Dark Energy Spectroscopic Instrument (DESI) baryon acoustic oscillation, the Planck 2018 CMB and Pantheon supernova data, we report the first search for the primordial gravitational waves (GWs) based on the evolving DE, which reveals a non-zero tensor-to-scalar ratio <em>r</em> at <span><math><mo>∼</mo><mn>2</mn><mi>σ</mi></math></span> significance level with the bestfit <span><math><msub><mrow><mi>r</mi></mrow><mrow><mn>0.05</mn></mrow></msub><mo>∼</mo><mn>0.01</mn></math></span>. Our result can be confirmed further by upcoming CMB B-mode polarization experiments and ongoing cosmological surveys. Our work indicates that the significant signal of primordial GWs might have already emerged in CMB B-mode data, however, its detection is depending significantly on our insight into the nature of DE, opening an unexpected window for comprehending our primordial universe in new era of cosmological surveys.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"868 ","pages":"Article 139744"},"PeriodicalIF":4.3,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144714338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Isotopic transparency in central Xe+Sn collisions at 100 MeV/nucleon","authors":"A. Le Fèvre ,&nbsp;A. Chbihi ,&nbsp;Q. Fable ,&nbsp;T. Génard ,&nbsp;J. Łukasik ,&nbsp;W. Trautmann ,&nbsp;K. Turzó ,&nbsp;R. Bougault ,&nbsp;S. Hudan ,&nbsp;O. Lopez ,&nbsp;W.F.J. Müller ,&nbsp;C. Schwarz ,&nbsp;C. Sfienti ,&nbsp;G. Verde ,&nbsp;M. Vigilante ,&nbsp;B. Zwiegliński","doi":"10.1016/j.physletb.2025.139749","DOIUrl":"10.1016/j.physletb.2025.139749","url":null,"abstract":"<div><div>A new method, based on comparing isotopic yield ratios measured at forward and sideward polar angles and on cross-bombarding heavy nuclei with different neutron-to-proton ratios, is used to quantify the stopping power of nuclear matter in heavy-ion collisions. For central collisions of isotopically separated ^124,129Xe+^112,124Sn at 100 MeV/nucleon bombarding energy, measured with the 4<em>π</em> multidetector INDRA at GSI, a moderate transparency is deduced for hydrogen isotopes, whereas for heavier fragmentation products with atomic number <span><math><mi>Z</mi><mo>≥</mo><mn>3</mn></math></span> a high transparency exceeding 50% is observed. An anomalously large transparency is found for alpha particles, and possible explanations are presented.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"868 ","pages":"Article 139749"},"PeriodicalIF":4.5,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144748871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Playing with lepton asymmetry at the resonant production of sterile neutrino dark matter","authors":"Dmitry Gorbunov ,&nbsp;Dmitry Kalashnikov ,&nbsp;George Krugan","doi":"10.1016/j.physletb.2025.139750","DOIUrl":"10.1016/j.physletb.2025.139750","url":null,"abstract":"<div><div>We examine the sterile neutrino dark matter production in the primordial plasma with lepton asymmetry unequally distributed over different neutrino flavors. We argue that with the specific flavor fractions, one can mitigate limits from the Big Bang Nucleosynthesis on the sterile-active neutrino mixing angle and sterile neutrino mass. It happens due to cancellation of the neutrino flavor asymmetries in active neutrino oscillations, which is more efficient in the case of inverse hierarchy of active neutrino masses and does not depend on the value of CP-phase. This finding opens a window of lower sterile-active mixing angles. Likewise, we show that, with lepton asymmetry disappearing from the plasma at certain intermediate stages of the sterile neutrino production, the spectrum of produced neutrinos becomes much colder, which weakens the limits on the model parameter space from observations of cosmic small-scale structures (Ly-<em>α</em> forest, galaxy counts, etc.). This finding reopens the region of lighter sterile neutrinos. The new region may be explored with the next generation of X-ray telescopes searching for the inherent peak signature provided by the dark matter sterile neutrino radiative decays in the Galaxy.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"868 ","pages":"Article 139750"},"PeriodicalIF":4.3,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144687436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Massive particles tunneling from quantum Oppenheimer-Snyder black holes and black hole entropy","authors":"Hongwei Tan, Kui Xiao","doi":"10.1016/j.physletb.2025.139741","DOIUrl":"https://doi.org/10.1016/j.physletb.2025.139741","url":null,"abstract":"In this paper, we investigate the tunneling process of massive scalar particles from a quantum Oppenheimer-Snyder black hole using the tunneling approach proposed by Parikh and Wilczek. We compute the emission rate of these tunneling particles, which includes quantum correction terms compared to the result in classical General Relativity. These correction terms arise from loop quantum gravity effects. Following the scheme outlined in <ce:cross-refs ref>[1,2]</ce:cross-refs>, we derive the entropy of the black hole. Consistent with the universal black hole entropy formula in the context of quantum gravity, our findings include a logarithmic correction.","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"10 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144664866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}