The European Physical Journal C最新文献_第9页

Logarithmic corrections to O((a^2)) effects in lattice QCD with unrooted staggered quarks 无根交错夸克晶格QCD中O（(a^2)）效应的对数修正

IF 4.8 2区物理与天体物理

The European Physical Journal C Pub Date : 2026-04-26 DOI: 10.1140/epjc/s10052-026-15460-2

Nikolai Husung

引用次数: 0

Possible mixing between elementary and bound state fields in the (tbar{t}) production excess at the LHC 大型强子对撞机(tbar{t})生产过剩中基本态场和束缚态场可能的混合

IF 4.8 2区物理与天体物理

The European Physical Journal C Pub Date : 2026-04-26 DOI: 10.1140/epjc/s10052-026-15661-9

Yoshiki Matsuoka

{"title":"Possible mixing between elementary and bound state fields in the (tbar{t}) production excess at the LHC","authors":"Yoshiki Matsuoka","doi":"10.1140/epjc/s10052-026-15661-9","DOIUrl":"10.1140/epjc/s10052-026-15661-9","url":null,"abstract":"<div>Recent report by CMS Collaboration on the excess of top and anti-top pair production is studied, under the hypothesis of the coexistence of a toponium ((eta _t)) and an additional elementary field ((Psi )). We examine the scenario where toponium and an additional field are mixed, and consider the plausible scenarios in that case. Two scenarios are examined: one is the minimal model with (Psi ) close to the inert Higgs doublet, and the other is embedded into the two Higgs doublet models (2HDM), where (Psi ) is one of the two Higgs scalars after transforming the basis. The value of each coupling constant is restricted by the Multicritical Point Principle (MPP). Consistency with the data gives constraints on a mixing angle (theta (-45^circ le theta le 45^circ )), with which the mass eigenstate (Psi ^prime ) contributing to the excess is defined by (Psi ^prime =Psi cos theta + eta _tsin theta ). The obtained results are (|theta | le 13^{circ }) for the minimum scenario, and (|theta | le 1^{circ }) for the second scenario of 2HDM (Type II and Y). We also briefly discuss the comparison with Type I and X.\u0000</div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 4","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-15661-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796697","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

Starobinsky inflation and the latest CMB data: a subtle tension? 斯塔宾斯基膨胀和最新的宇宙微波背景辐射数据：微妙的紧张关系？

IF 4.8 2区物理与天体物理

The European Physical Journal C Pub Date : 2026-04-26 DOI: 10.1140/epjc/s10052-026-15686-0

J. Bezerra-Sobrinho, L. G. Medeiros

{"title":"Starobinsky inflation and the latest CMB data: a subtle tension?","authors":"J. Bezerra-Sobrinho, L. G. Medeiros","doi":"10.1140/epjc/s10052-026-15686-0","DOIUrl":"10.1140/epjc/s10052-026-15686-0","url":null,"abstract":"<div>We analyze the Starobinsky inflation model and the impact of curvature corrections, particularly a cubic (R^3) term, to assess their behavior in light of the latest observational results from the Atacama Cosmology Telescope (ACT). With the recent sixth data release (DR6), the scalar spectral index was measured to be (n_s=0.9752 pm 0.0030), when combined with BAO data from DESI DR2, which appears to exclude the pure Starobinsky model at approximately the (2sigma ) level. In this paper, we implement the Starobinsky inflationary potential directly into the CLASS code, without relying on the slow-roll approximation, and we constrain the number of e-folds of inflation (N_k) using a theoretically motivated range derived from reheating considerations and standard couplings between matter fields and gravity. We show that it is still possible to identify a significant region of parameter space where the Starobinsky model remains highly consistent with the latest observational data. While the pure Starobinsky model remains a compelling candidate for cosmic inflation, we explore how including a cubic (R^3) term can shift its predictions to better align with the Planck and ACT measurements.\u0000\u0000</div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 4","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-15686-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796626","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

Exploring fermionic dark matter in the presence of scalar leptoquarks 在标量轻夸克存在下探索费米子暗物质

IF 4.8 2区物理与天体物理

The European Physical Journal C Pub Date : 2026-04-25 DOI: 10.1140/epjc/s10052-026-15682-4

Shyamashish Dey, Santosh Kumar Rai

引用次数: 0

Bounds on the photon sphere radius for spherically symmetric black holes in ({varvec{n}})-dimensional Einstein gravity 在({varvec{n}})维爱因斯坦引力下球对称黑洞的光子球半径边界

IF 4.8 2区物理与天体物理

The European Physical Journal C Pub Date : 2026-04-25 DOI: 10.1140/epjc/s10052-026-15623-1

Yong Song, Jiaqi Fu, Yiting Cen

{"title":"Bounds on the photon sphere radius for spherically symmetric black holes in ({varvec{n}})-dimensional Einstein gravity","authors":"Yong Song, Jiaqi Fu, Yiting Cen","doi":"10.1140/epjc/s10052-026-15623-1","DOIUrl":"10.1140/epjc/s10052-026-15623-1","url":null,"abstract":"<div>The photon sphere, a hypersurface of null circular geodesics, plays a fundamental role in characterizing black hole spacetimes, influencing phenomena such as black hole shadows, gravitational lensing, and quasinormal modes. In this work, we derive both upper and lower bounds on the photon sphere radius for static, spherically symmetric, asymptotically flat black holes within n-dimensional Einstein gravity ((nge 4)), assuming an anisotropic matter field satisfying the weak energy condition and a non-positive trace of the energy–momentum tensor. For the upper bound, we obtain (r_gamma le [(n-1)M]^{frac{1}{n-3}},) where M is the ADM mass. In the four-dimensional case ((n=4)), this reduces to (r_gamma le 3M,) in agreement with previous results. For the lower bound, under the additional assumption that (|r^{n-1}p_r(r)|) is monotonically decreasing, we prove (r_gamma ge (frac{n-1}{2})^{1/(n-3)}r_H,) where (r_H) is the radius of the outer event horizon; for (n=4) this gives (r_gamma ge frac{3}{2}r_H,) also consistent with previous four-dimensional result. These results provide dimension-dependent geometric constraints that generalize well-known four-dimensional bounds to a specific class of higher-dimensional black holes (described by a Tangherlini-type metric) and deepen our understanding of spacetime structure in higher-dimensional gravitational theories.\u0000\u0000</div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 4","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-15623-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738903","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

Quantum-improved wormholes in the Dekel–Zhao dark matter halo Dekel-Zhao暗物质光晕中的量子改进虫洞

IF 4.8 2区物理与天体物理

The European Physical Journal C Pub Date : 2026-04-25 DOI: 10.1140/epjc/s10052-026-15676-2

Jonathan A. Rebouças, Celio R. Muniz, Francisco Bento Lustosa, Edson Otoniel

{"title":"Quantum-improved wormholes in the Dekel–Zhao dark matter halo","authors":"Jonathan A. Rebouças, Celio R. Muniz, Francisco Bento Lustosa, Edson Otoniel","doi":"10.1140/epjc/s10052-026-15676-2","DOIUrl":"10.1140/epjc/s10052-026-15676-2","url":null,"abstract":"<div>In this work, we investigate novel traversable wormhole solutions within the framework of Asymptotically Safe Gravity (ASG), in the presence of a surrounding matter distribution described by the Dekel–Zhao profile. By considering the ASG renormalization group flow in the infrared (IR) regime, we show that quantum gravitational corrections allow these structures to exist at astrophysical scales, where the Dekel–Zhao matter distribution and ASG effects together determine the geometric stability and observational signatures of the wormhole. Thus, the scale-dependent gravitational coupling G(k), derived from ASG in the IR regime, is incorporated directly into the field equations, providing a consistent description of quantum gravitational corrections at astrophysical scales. The combined effects of the running coupling (parameterized by (xi )) and the dark matter characteristics determine the geometric structure and physical viability of the wormhole. The solutions satisfy the flare-out and asymptotic flatness conditions within restricted parameter domains. The Null Energy Condition is necessarily violated at the throat, with the ASG corrections strengthening the exotic behavior required to sustain the wormhole geometry. This interpretation is reinforced by the modified Tolman–Oppenheimer–Volkoff analysis, which shows that the repulsive quantum contributions induced by ASG counterbalance gravitational collapse. Phenomenologically, the shadow radius of the wormhole increases nearly linearly with (xi ), lying within the Event Horizon Telescope bounds for Sgr A* when (xi /M simeq 0.8)–0.9, suggesting that ASG-corrected traversable wormholes in a dark matter environment described by the Dekel–Zhao profile may exhibit shadow properties compatible with current observational bounds in the strong-field regime.\u0000\u0000</div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 4","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-15676-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738906","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

High-energy decays and weak quantum measurements 高能衰变和弱量子测量

IF 4.8 2区物理与天体物理

The European Physical Journal C Pub Date : 2026-04-25 DOI: 10.1140/epjc/s10052-026-15694-0

Alan J. Barr

引用次数: 0

Neural simulation-based inference of the Higgs trilinear self-coupling via off-shell Higgs production 基于神经模拟的希格斯三线性自耦合的脱壳希格斯产生推理

IF 4.8 2区物理与天体物理

The European Physical Journal C Pub Date : 2026-04-25 DOI: 10.1140/epjc/s10052-026-15605-3

Aishik Ghosh, Maximilian Griese, Ulrich Haisch, Tae Hyoun Park

{"title":"Neural simulation-based inference of the Higgs trilinear self-coupling via off-shell Higgs production","authors":"Aishik Ghosh, Maximilian Griese, Ulrich Haisch, Tae Hyoun Park","doi":"10.1140/epjc/s10052-026-15605-3","DOIUrl":"10.1140/epjc/s10052-026-15605-3","url":null,"abstract":"<div>One of the forthcoming major challenges in particle physics is the experimental determination of the Higgs trilinear self-coupling. While efforts have largely focused on on-shell double- and single-Higgs production in proton-proton collisions, off-shell Higgs production has also been proposed as a valuable complementary probe. In this article, we design a hybrid neural simulation-based inference (NSBI) approach to construct a likelihood of the Higgs signal incorporating modifications from the Standard Model effective field theory (SMEFT), relevant background processes, and quantum interference effects. It leverages the training efficiency of matrix-element-enhanced techniques, which are vital for robust SMEFT applications, while also incorporating the practical advantages of classification-based methods for effective background estimates. We demonstrate that our NSBI approach achieves sensitivity close to the theoretical optimum and provide expected constraints for the high-luminosity upgrade of the Large Hadron Collider. While we primarily concentrate on the Higgs trilinear self-coupling, we also consider constraints on other SMEFT operators that affect off-shell Higgs production.\u0000</div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 4","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-15605-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796929","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

Cosmic expansion driven by gravitational particle production: toward a complete cosmological scenario 由引力粒子产生驱动的宇宙膨胀：走向一个完整的宇宙场景

IF 4.8 2区物理与天体物理

The European Physical Journal C Pub Date : 2026-04-25 DOI: 10.1140/epjc/s10052-026-15631-1

P. W. R. Lima, J. A. S. Lima

{"title":"Cosmic expansion driven by gravitational particle production: toward a complete cosmological scenario","authors":"P. W. R. Lima, J. A. S. Lima","doi":"10.1140/epjc/s10052-026-15631-1","DOIUrl":"10.1140/epjc/s10052-026-15631-1","url":null,"abstract":"<div>A dark-energy-free cosmological model ((Omega _{DE} equiv 0)) based on gravitationally induced adiabatic particle creation is proposed. The thermodynamics of particle production yields an effective negative pressure that drives both primordial inflation and late-time cosmic acceleration. The model, characterized by four components and two free parameters ((alpha ,) (beta )), reproduces a (Lambda )CDM-like expansion for suitable (alpha ,) while (beta ) introduces small but testable deviations from the cosmic concordance model. Constraints from type Ia Supernovae (Pantheon+SH0ES) and H(z) data indicate (beta simeq 0.13,) suggesting a mild departure from standard cosmology and possible relief of the (H_0) and (S_8) tensions. The resulting classical cosmology evolves smoothly between two extreme de Sitter phases, offering a singularity-free, unified scenario that beyond solving old cosmological puzzles opens a new perspective to handle the tensions plaguing the current cosmic concordance model.\u0000</div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 4","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-15631-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738928","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

Masses of purely top-quark bound states: toponium and the triply-top baryon 纯顶夸克束缚态的质量：toponium和三顶重子

IF 4.8 2区物理与天体物理

The European Physical Journal C Pub Date : 2026-04-25 DOI: 10.1140/epjc/s10052-026-15679-z

Z. Rajabi Najjar, K. Azizi

{"title":"Masses of purely top-quark bound states: toponium and the triply-top baryon","authors":"Z. Rajabi Najjar, K. Azizi","doi":"10.1140/epjc/s10052-026-15679-z","DOIUrl":"10.1140/epjc/s10052-026-15679-z","url":null,"abstract":"<div>We investigate the pseudoscalar ((eta _t)) and vector ((psi _t)) toponium states, as well as the triply-top baryon ((Omega _{ttt})), using the QCD sum-rule method. This study was motivated by the recent observation of a pseudoscalar enhancement near the (tbar{t}) threshold, reported by the CMS and ATLAS collaborations with a statistical significance exceeding (5sigma ). In the calculations, we consider both the perturbative and nonperturbative contributions, with the nonperturbative operators taken into account up to dimension eight. The results obtained for the pseudoscalar toponium provide a theoretical estimate that is consistent with the near-threshold events observed in recent experimental studies. The calculated negative binding energy for both the pseudoscalar and vector toponium states reflects the strong correlation within the (tbar{t}) system and can be interpreted as (tbar{t}) bound states, while the calculated central mass for the (Omega _{ttt}) slightly exceeds the central value of the sum of the constituent top-quark masses. The results of this study can provide a precise theoretical guide for future experimental investigations of these states, which are composed entirely of top quarks, at high-energy colliders such as the LHC and future facilities like the FCC.\u0000</div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 4","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-15679-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738804","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