Physics Letters B最新文献

{"title":"The Large Magellanic Cloud as a source of the highest energy cosmic rays","authors":"Roger Clay ,&nbsp;Tadeusz Wibig","doi":"10.1016/j.physletb.2025.139903","DOIUrl":"10.1016/j.physletb.2025.139903","url":null,"abstract":"<div><div>The Pierre Auger Observatory has published properties of the 100 highest-energy cosmic ray events (to energies above 100 EeV) which it recorded over a 17 year period. We have examined the directional properties of these events and have taken particular note of the most energetically extreme events. We find that the most energetic events have directions which are grouped in a non-random way at the 1 % level. There is an apparent clustering in a limited region of the sky. Close to that direction is found Centaurus A, which has long been considered as a source of such particles, but we also note that a close-by dwarf galaxy, the Large Magellanic Cloud (LMC) is closer in angular terms. We examine the possibility that the LMC might be a source of observed cosmic rays at the highest energies.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"870 ","pages":"Article 139903"},"PeriodicalIF":4.5,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145269208","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":"Could regular primordial black holes be dark matter?","authors":"Mohsen Khodadi","doi":"10.1016/j.physletb.2025.139922","DOIUrl":"10.1016/j.physletb.2025.139922","url":null,"abstract":"<div><div>The recent proposal proposed by Paul Davies and colleagues [Phys. Rev. D <strong>111</strong> (2025) no.10, 103512] that regular primordial black holes (RPBHs) form stable, zero-temperature remnants and could thereby constitute dark matter is critically examined. While the introduction of a fundamental length scale indeed regulates the Hawking temperature, preventing its divergence, we show that the evaporation timescale for such RPBHs is infinite. This result holds generically for analytic regular black hole spacetimes under standard adiabatic and quasi-static evolution. Consequently, RPBHs never actually reach a true remnant state within any finite time, but instead persist as slowly evaporating objects with a non-zero luminosity. When the combined emission from a cosmological population of these near-remnants is considered, the resulting radiation is found to violate stringent observational constraints from the cosmic microwave background and extragalactic gamma-ray backgrounds. Therefore, low-mass RPBHs are not viable dark matter candidates.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"870 ","pages":"Article 139922"},"PeriodicalIF":4.5,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145269177","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":"LIV-decoherence on gravitational cat states","authors":"Iarley P. Lobo ,&nbsp;Kelvin Sampaio ,&nbsp;Gislaine Varão ,&nbsp;Moises Rojas ,&nbsp;Valdir B. Bezerra","doi":"10.1016/j.physletb.2025.139923","DOIUrl":"10.1016/j.physletb.2025.139923","url":null,"abstract":"<div><div>Inspired by approaches based on the stochastic generalized uncertainty principle, we propose a Lindblad equation derived from the quantization of a stochastic modified dispersion relation in a Lorentz Invariance Violation (LIV) scenario. This framework enables us to investigate decoherence effects in a system of particles exhibiting gravitationally induced entanglement. We analyze the impact of LIV on entanglement (quantified by concurrence) considering systematic and stochastic effects.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"870 ","pages":"Article 139923"},"PeriodicalIF":4.5,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145269178","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":"Erratum: Disappearance of partonic collectivity in √ sNN = 3 GeV Au+Au collisions at RHIC [Phys. Lett. B 827, 137003 (2022)]","authors":"STAR Collaboration ,&nbsp;D. Isenhower ,&nbsp;J.L. Drachenberg ,&nbsp;M. Daugherity ,&nbsp;L. Adamczyk ,&nbsp;L. Fulek ,&nbsp;M. Przybycien ,&nbsp;R. Sikora ,&nbsp;I. Alekseev ,&nbsp;D.N. Svirida ,&nbsp;I.G. Bordyuzhin ,&nbsp;D.G. Underwood ,&nbsp;H.M. Spinka ,&nbsp;M. Zurek ,&nbsp;A. Hamed ,&nbsp;F.M. Fawzi ,&nbsp;M.S. Abdallah ,&nbsp;J. Jia ,&nbsp;A. Jentsch ,&nbsp;A. Kiselev ,&nbsp;T. Liu","doi":"10.1016/j.physletb.2025.139912","DOIUrl":"10.1016/j.physletb.2025.139912","url":null,"abstract":"<div><div>We report on the measurements of directed flow <span><math><msub><mi>v</mi><mn>1</mn></msub></math></span> and elliptic flow <span><math><msub><mi>v</mi><mn>2</mn></msub></math></span> for hadrons (<span><math><msup><mi>π</mi><mo>±</mo></msup></math></span>, <span><math><msup><mi>K</mi><mo>±</mo></msup></math></span>, <span><math><msubsup><mi>K</mi><mrow><mi>S</mi></mrow><mn>0</mn></msubsup></math></span>, <span><math><mi>p</mi></math></span>, <span><math><mi>ϕ</mi></math></span>, <span><math><mstyle><mi>Λ</mi></mstyle></math></span> and <span><math><msup><mstyle><mi>Ξ</mi></mstyle><mo>−</mo></msup></math></span>) from Au+Au collisions at <span><math><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt></math></span> = 3 GeV and <span><math><msub><mi>v</mi><mn>2</mn></msub></math></span> for (<span><math><msup><mi>π</mi><mo>±</mo></msup></math></span>, <span><math><msup><mi>K</mi><mo>±</mo></msup></math></span>, <span><math><mi>p</mi></math></span> and <span><math><mover><mrow><mi>p</mi></mrow><mo>‾</mo></mover></math></span>) at 27 and 54.4 GeV with the STAR experiment. While at the two higher energy midcentral collisions the number-of-constituent-quark (NCQ) scaling holds, at 3 GeV the <span><math><msub><mi>v</mi><mn>2</mn></msub></math></span> at midrapidity is negative for all hadrons and the NCQ scaling is absent. In addition, the <span><math><msub><mi>v</mi><mn>1</mn></msub></math></span> slopes at midrapidity for almost all observed hadrons are found to be positive, implying dominant repulsive baryonic interactions. The features of negative <span><math><msub><mi>v</mi><mn>2</mn></msub></math></span> and positive <span><math><msub><mi>v</mi><mn>1</mn></msub></math></span> slope at 3 GeV can be reproduced with a baryonic mean-field in transport model calculations. These results imply that the medium in such collisions is likely characterized by baryonic interactions.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"870 ","pages":"Article 139912"},"PeriodicalIF":4.5,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145311769","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":"Detection of the stochastic gravitational wave background with the space-based gravitational-wave detector network","authors":"Jun Cheng ,&nbsp;En-Kun Li ,&nbsp;Jianwei Mei","doi":"10.1016/j.physletb.2025.139890","DOIUrl":"10.1016/j.physletb.2025.139890","url":null,"abstract":"<div><div>The stochastic gravitational wave background (SGWB) is one of the main detection targets for future millihertz space-based gravitational-wave observatories such as the laser interferometer space antenna (LISA), TianQin, and Taiji. For a single LISA-like detector, a null-channel method was developed to identify the SGWB by integrating data from the A and E channels with a noise-only T channel. However, the noise monitoring channel will not be available if one of the laser interferometer arms fails. By combining these detectors, it will be possible to build detector networks to search for SGWB via cross-correlation analysis. In this work, we developed a Bayesian data analysis method based on time delay interferometry (TDI) Michelson-type channel. We then investigate the detectability of the TianQin-LISA detector network for various isotropic SGWB. Assuming a three-month observation, the TianQin-LISA detector network could be able to confidently detect SGWB with energy density as low as <span><math><mrow><msub><mstyle><mi>Ω</mi></mstyle><mrow><mrow><mi>P</mi></mrow><mi>L</mi></mrow></msub><mo>=</mo><mn>6.0</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>13</mn></mrow></msup></mrow></math></span>, <span><math><mrow><msub><mstyle><mi>Ω</mi></mstyle><mrow><mrow><mi>F</mi></mrow><mi>l</mi><mi>a</mi><mi>t</mi></mrow></msub><mo>=</mo><mn>2.0</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>12</mn></mrow></msup></mrow></math></span> and <span><math><mrow><msub><mstyle><mi>Ω</mi></mstyle><mrow><mrow><mi>S</mi></mrow><mi>P</mi></mrow></msub><mo>=</mo><mn>1.2</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>12</mn></mrow></msup></mrow></math></span> for power-law, flat and single-peak models, respectively.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"870 ","pages":"Article 139890"},"PeriodicalIF":4.5,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145333685","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":"ACT-ing on inflation: Implications of non bunch-Davies initial condition and reheating on single-field slow roll models","authors":"Suvashis Maity","doi":"10.1016/j.physletb.2025.139913","DOIUrl":"10.1016/j.physletb.2025.139913","url":null,"abstract":"<div><div>We investigate a class of slow roll inflationary models in light of the recent Cosmic Microwave Background constraints from Planck 2018, ACT DR6, DESI DR1, and BICEP/<em>Keck</em> 2018. The combined dataset favors a higher value of the scalar spectral index <span><math><mrow><msub><mi>n</mi><msub><mrow></mrow><mrow><mi>S</mi></mrow></msub></msub><mo>=</mo><mn>0.9743</mn><mo>±</mo><mn>0.0034</mn></mrow></math></span>, which places increased pressure on several conventional inflationary scenarios. In this study, we analyze the observational viability of various well-motivated models, including the <span><math><mi>α</mi></math></span>-attractor E- and T-models, chaotic inflation, hilltop inflation, and natural inflation. We incorporate the effects of a post-inflationary phase of reheating and examine how the dynamics of reheating influence the predictions in the <span><math><mrow><msub><mi>n</mi><msub><mrow></mrow><mrow><mi>S</mi></mrow></msub></msub><mo>−</mo><mi>r</mi></mrow></math></span> plane. We also impose a lower bound on the reheating temperature based on the constraint from the effective number of relativistic species (<span><math><mrow><mstyle><mi>Δ</mi></mstyle><msub><mi>N</mi><mrow><mi>eff</mi></mrow></msub></mrow></math></span>) arising from primordial gravitational waves. While reheating improves agreement with observations for some models, significant regions of parameter space remain disfavored. Finally, we explore the impact of a non Bunch-Davies initial state and demonstrate that it can substantially improve the fit to the <span><math><mrow><msub><mi>n</mi><msub><mrow></mrow><mrow><mi>S</mi></mrow></msub></msub><mo>−</mo><mi>r</mi></mrow></math></span> data across a broader class of inflationary models, thereby offering a potentially viable mechanism for reconciling theory with the latest observations.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"870 ","pages":"Article 139913"},"PeriodicalIF":4.5,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145229430","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":"Revisiting η′(958) nuclear states","authors":"E. Friedman,&nbsp;A. Gal","doi":"10.1016/j.physletb.2025.139916","DOIUrl":"10.1016/j.physletb.2025.139916","url":null,"abstract":"<div><div>Observing <span><math><msup><mi>η</mi><mo>′</mo></msup></math></span>-nuclear quasibound states requires that the <span><math><msup><mi>η</mi><mo>′</mo></msup></math></span>-nuclear potential is both sufficiently attractive and weakly absorptive, as confirmed by the CBELSA/TAPS collaboration analysis of inclusive <span><math><msup><mi>η</mi><mo>′</mo></msup></math></span> production experiments on nuclear targets, including liquid hydrogen (LH<span><math><msub><mrow></mrow><mn>2</mn></msub></math></span>). Here we present an alternative derivation of the <span><math><msup><mi>η</mi><mo>′</mo></msup></math></span>-nuclear potential, constrained by near-threshold <span><math><mrow><mi>p</mi><mi>p</mi><mo>→</mo><mi>p</mi><mi>p</mi><msup><mi>η</mi><mo>′</mo></msup></mrow></math></span> and <span><math><mrow><mi>γ</mi><mi>p</mi><mo>→</mo><msup><mi>η</mi><mo>′</mo></msup><mi>p</mi></mrow></math></span> production experiments on a free proton. The resulting <span><math><msup><mi>η</mi><mo>′</mo></msup></math></span>-nuclear potential is weakly attractive and strongly absorptive, to the extent that observation of clear signals of <span><math><msup><mi>η</mi><mo>′</mo></msup></math></span>-nuclear quasibound states is unlikely. Possible exceptions resulting from the dynamics of the nearby <span><math><mrow><mi>I</mi><mo>=</mo><mfrac><mn>1</mn><mn>2</mn></mfrac></mrow></math></span><span><math><mrow><msup><mi>J</mi><mi>π</mi></msup><mo>=</mo><msup><mrow><mo>(</mo><mfrac><mn>1</mn><mn>2</mn></mfrac><mo>)</mo></mrow><mo>−</mo></msup></mrow></math></span> nucleon resonance <span><math><msup><mi>N</mi><mo>*</mo></msup></math></span>(1895) are briefly discussed.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"870 ","pages":"Article 139916"},"PeriodicalIF":4.5,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145333680","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":"Superradiant bound states of charged scalars around Melvin-Kerr black holes","authors":"Haryanto M. Siahaan","doi":"10.1016/j.physletb.2025.139925","DOIUrl":"10.1016/j.physletb.2025.139925","url":null,"abstract":"<div><div>We investigate superradiant bound states of a charged, massive scalar in the Melvin-Kerr spacetime, a rotating black hole immersed in an external magnetic field, working in the weak-field regime <span><math><mrow><mi>b</mi><mi>M</mi><mo>≪</mo><mn>1</mn></mrow></math></span>. We adopt a gauge with <span><math><mrow><msub><mi>A</mi><mi>t</mi></msub><mspace></mspace><mo>→</mo><mspace></mspace><mn>0</mn></mrow></math></span> at spatial infinity, thereby removing spurious <span><math><mrow><mn>1</mn><mo>/</mo><mi>a</mi></mrow></math></span> artifacts in the <span><math><mrow><mi>a</mi><mspace></mspace><mo>→</mo><mspace></mspace><mn>0</mn></mrow></math></span> limit, and show that the Klein–Gordon equation separates so that the radial dynamics can be cast in Schrödinger-like form. The effective potential exhibits a universal large-<span><math><mi>r</mi></math></span> tail with both <span><math><mrow><mn>1</mn><mo>/</mo><mi>r</mi></mrow></math></span> and <span><math><mrow><mn>1</mn><mo>/</mo><msup><mi>r</mi><mn>2</mn></msup></mrow></math></span> corrections controlled by the magnetic coupling <span><math><mrow><mi>b</mi><mi>m</mi><mi>q</mi></mrow></math></span>. Using a far-zone Whittaker reduction we derive a simple trapping criterion that captures when a potential well forms outside the horizon. Combining this with the magnetically shifted superradiant band at the horizon and with the decay requirement at infinity yields an instability window in which superradiantly amplified quasi-bound states exist. The criterion reduces continuously to the standard Kerr bound in the limit <span><math><mrow><mi>b</mi><mo>→</mo><mn>0</mn></mrow></math></span>, which provides a nontrivial consistency check. Numerical profiles of the effective potential illustrate parameter sets with and without trapping, clarifying how the magnetic field and the azimuthal number compete to enhance or to quench the instability.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"870 ","pages":"Article 139925"},"PeriodicalIF":4.5,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145227626","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":"Scale-anomaly-induced binding pressure in hadrons","authors":"Daisuke Fujii ,&nbsp;Mitsuru Tanaka","doi":"10.1016/j.physletb.2025.139872","DOIUrl":"10.1016/j.physletb.2025.139872","url":null,"abstract":"<div><div>The effect of the QCD scale anomaly on the internal pressure distribution of hadrons is studied based on the trace-traceless decomposition of the energy-momentum tensor. Using recent model-independent results of gravitational form factors as input, the pressure distributions of both pions and nucleons are analyzed in the instant form and the light-front form. It is found that, in all cases, the scale anomaly dominantly generates the negative binding pressure. This result suggests that the phenomenon is a universal feature, independent of models, types of hadrons, and the choice of form.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"870 ","pages":"Article 139872"},"PeriodicalIF":4.5,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145269180","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":"Dark matter: Red or blue?","authors":"A. Acar,&nbsp;C. Isaacson,&nbsp;M. Bashkanov,&nbsp;D.P. Watts","doi":"10.1016/j.physletb.2025.139920","DOIUrl":"10.1016/j.physletb.2025.139920","url":null,"abstract":"<div><div>We report the first calculation of light scattering on heavy dark matter (DM) particles. We show that despite the fact that DM has no direct coupling to photons, the light-DM(<span><math><mrow><mi>γ</mi><mi>χ</mi></mrow></math></span>) (<span><math><mrow><msub><mi>m</mi><mi>χ</mi></msub><mo>∼</mo><mn>1</mn></mrow></math></span> TeV) cross-section is non-vanishing, albeit small. The cross section, calculated within the Standard Model (SM) framework (no BSM extensions),is particularly large in the case of heavy Weakly Interacting Massive Particles (WIMP). Combined with astrophysical observation, these results can constrain existing WIMP DM models in favor of lighter DM, <span><math><mrow><msub><mi>M</mi><mi>χ</mi></msub><mo>&lt;</mo><mo>&lt;</mo><msub><mi>M</mi><mrow><mi>Planck</mi></mrow></msub></mrow></math></span>, (axions, composite DM, etc.) or non-weakly interacting pure gravitational DM. We also show that the energy dependence of light scattering on dark matter should make the DM colored - red in the case of weak-DM and blue for the gravitational-DM, when a white background light is passing through. Gravitational scattering of light on DM particles also leads to non-trivial polarization effects, which might be easier to detect than the deflection of light from the scattering on DM particles, <span><math><mrow><mi>γ</mi><mi>χ</mi><mo>→</mo><mi>γ</mi><mi>χ</mi></mrow></math></span>.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"870 ","pages":"Article 139920"},"PeriodicalIF":4.5,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145269209","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}