The European Physical Journal C最新文献

{"title":"Reconstructing gamma-ray burst energy relations with observational H(z) data in a neural network framework","authors":"Nilanjana Bagchi Aurpa,&nbsp;Abha Dev Habib,&nbsp;Nisha Rani","doi":"10.1140/epjc/s10052-026-16318-3","DOIUrl":"10.1140/epjc/s10052-026-16318-3","url":null,"abstract":"<div><p>Gamma-ray bursts (GRBs) offer a powerful probe of the cosmic expansion history far beyond the redshift range accessible to Type Ia supernovae. However, the study of cosmological models using GRBs is hindered by the circularity problem, which arises from assuming a fiducial cosmological model during GRB luminosity distance calibration. In this work, we perform a model-independent calibration of GRB luminosity relations using observational measurements of the Hubble parameter from the A220 and J220 compilations, thereby avoiding explicit cosmological assumptions. We employ an artificial neural network to reconstruct the calibration relation directly from the data. In addition, we implement a Bayesian neural network framework as an alternative approach, enabling a data-driven treatment of both statistical and systematic uncertainties. We use calibrated GRB samples to constrain the Amati relation and systematically compare the outcomes obtained from different calibration techniques and datasets. We find that the Amati relation slopes derived from the two neural network approaches are consistent with each other and with previous low-redshift calibrations obtained using model-independent methods. The Bayesian Neural Network approach provides a more robust framework for propagating uncertainties in the calibration procedure.\u0000\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 9","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-16318-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149133185","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}

{"title":"Pmt waveform simulation and reconstruction with conditional diffusion network","authors":"Kainan Liu,&nbsp;Jingyu Huang,&nbsp;Guihong Huang,&nbsp;Jianyi Luo","doi":"10.1140/epjc/s10052-026-16415-3","DOIUrl":"10.1140/epjc/s10052-026-16415-3","url":null,"abstract":"<div><p>Photomultiplier tubes (PMTs) are widely employed in particle and nuclear physics experiments. The accuracy of PMT waveform reconstruction directly impacts the vertex and energy resolution of detectors. A key challenge arises when multiple photons arrive within a few nanoseconds, making it difficult to resolve individual photoelectrons (PEs). Although supervised machine learning methods have surpassed traditional methods in performance, their practical applicability is limited by the lack of ground-truth PE labels in real data. To address this issue, we propose an innovative weakly supervised waveform simulation and reconstruction approach based on a bidirectional conditional diffusion network framework. The method is fully data-driven and requires only raw waveforms and coarse estimates of PE information as input. It first employs a PE-conditioned diffusion model to simulate realistic waveforms from PE sequences, thereby learning the features of overlapping waveforms. Subsequently, these simulated waveforms are used to train a waveform-conditioned diffusion model to reconstruct the PE sequences from waveforms, reinforcing the learning of features of overlapping waveforms. Through iterative refinement between the two conditional diffusion processes, the model progressively improves reconstruction accuracy. Experimental results demonstrate that the proposed method achieves an average normalized PE-number resolution over 1–5 p.e. that is about 1% worse than that of fully supervised learning, and a timing resolution that is about 25% worse.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 9","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-16415-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149133203","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}

{"title":"Carroll–Field–Jackiw term in nonlocal Lorentz-violating QED","authors":"J. R. Nascimento,&nbsp;A. Yu. Petrov,&nbsp;P. J. Porfírio,&nbsp;Ramires N. da Silva","doi":"10.1140/epjc/s10052-026-16399-0","DOIUrl":"10.1140/epjc/s10052-026-16399-0","url":null,"abstract":"<div><p>We investigate the radiative generation of the Carroll–Field–Jackiw (CFJ) term in nonlocal Lorentz- and CPT-violating extensions of quantum electrodynamics. Nonlocality is introduced in the fermionic sector through entire form factors depending on the Dirac operator. Using the Fréchet and derivative expansions of the one-loop fermionic determinant, we derive the induced CFJ contribution and analyze its ultraviolet behavior after Wick rotation. For one class of form factors, the loop integrals are absolutely convergent at finite nonlocality scale <span>(Lambda ,)</span> without requiring an additional UV regulator. For another class of form factors, the CFJ coefficient is defined through an Abel regularization prescription. In both cases, the CFJ structure is preserved and its coefficient is continuously modulated by the ratio between the fermion mass and the nonlocality scale. Thus, nonlocality removes the routing-, surface-term-, and UV-evanescent ambiguities of the finite-<span>(Lambda )</span> loop amplitude, although UV convergence alone does not imply complete prescription independence of the finite functional determinant.\u0000\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 9","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-16399-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149133204","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}

{"title":"Hyperbolic form factors for Yukawa interactions, and applications to the Earth","authors":"Pierre Fayet","doi":"10.1140/epjc/s10052-026-15933-4","DOIUrl":"10.1140/epjc/s10052-026-15933-4","url":null,"abstract":"<div><p>We define the hyperbolic form factor of a density distribution as its bilateral Laplace transform, related by duality or analytic continuation to its ordinary form factor.  For a sphere it is given by <span>(Phi (x != ! kR) =langle ,cosh ,vec k.vec r,rangle = langle ,frac{sinh kr}{kr},rangle )</span>, expanded as <span>(,sum _0^infty frac{x^{2n}}{(2n+1)! }, frac{langle r^{2n}rangle }{R^{2n}})</span>, and similarly for the form factor <span>( langle ,frac{sin kr}{kr},rangle )</span>. It is also obtained from the bilateral Laplace transform of <span>(2pi r,rho (|r|))</span>, and enters in the determination of the outside Yukawa potential induced by a new charge for a mediator of mass <span>(m= k=)</span> <span>(1/lambda )</span>.  <span>(Phi (x))</span> may be expressed as <span>(frac{3}{x^3},(x,cosh x - sinh x) times {{bar{rho }}} (x)/rho _0)</span>, where <span>({{bar{rho }}}(x))</span> is an effective density decreasing (for <span>(drho /dr &lt;0))</span> from the average <span>(rho _0)</span> at small <i>x</i>, down to the density <span>(rho (R))</span> near the surface. An inversion formula allows one to recover the density distribution <span>(rho (r))</span> from an analytic continuation of <span>(Phi (x))</span>, as <span>(rho (r) =rho _0, (2R/3pi r)int _0^infty Phi (ix) , sin (xfrac{r}{R}) x,dx,)</span>.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 9","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-15933-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132890","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}

{"title":"Type I + II seesaw model in light of the new neutrino oscillation measurements","authors":"Maria Aguilar,&nbsp;Juan Carlos Helo,&nbsp;Toshihiko Ota,&nbsp;Farinaldo S. Queiroz,&nbsp;David Suarez,&nbsp;Amanda Rodríguez","doi":"10.1140/epjc/s10052-026-16328-1","DOIUrl":"10.1140/epjc/s10052-026-16328-1","url":null,"abstract":"<div><p>Global analysis of neutrino oscillation data slightly favors normal mass ordering. In this work, we investigate an extended scalar sector that naturally gives rise to a type I + II seesaw mechanism after spontaneous symmetry breaking and explore the interplay between collider physics and lepton flavor violation, adopting normal ordering. In particular, we focus on the rare muon decays <span>(mu rightarrow e gamma )</span> and <span>(mu rightarrow 3e)</span> and the same-sign dilepton searches at LHC, a canonical signature of a doubly charged scalar. We conclude that neither the precise value of the sum of the neutrino masses, taken from DESI data that favors <span>(sum m_nu =0.07)</span> eV, nor alternative cosmological fits which prefer a more relaxed limit <span>(sum m_nu =0.1)</span> eV, significantly changes the theoretical prediction for these rare decays. However, we observe an interesting interplay between collider physics and lepton flavor violation. In particular, we find that <span>(mu rightarrow 3e)</span> is more constraining than <span>(mu rightarrow egamma )</span>. The <span>(mu rightarrow 3e)</span> decay can yield a lower mass limit of 3 TeV on the doubly charged scalar, surpassing current LHC constraints in a dominant type II seesaw or in a mixed type I+II scenario. Nevertheless, LFV does not strongly constrain the dominant type I seesaw scenario.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 9","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-16328-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132590","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}

{"title":"Measurement of isolated-prompt photon–hadron correlations in Pb–Pb collisions at (sqrt{{s}_{{textrm{NN}}}} = 5.02) TeV","authors":"ALICE Collaboration","doi":"10.1140/epjc/s10052-026-16192-z","DOIUrl":"10.1140/epjc/s10052-026-16192-z","url":null,"abstract":"<div><p>The ALICE Collaboration has measured the azimuthal correlation between trigger isolated-prompt photons and associated charged hadrons in Pb–Pb collisions at the CERN LHC, at a centre-of-mass energy per nucleon pair of <span>(sqrt{s_{textrm{NN}}}~=~5.02)</span> TeV. The trigger isolated-prompt photons are measured in the transverse-momentum range <span>(18&lt;p_{textrm{T}}^{gamma }&lt;40)</span> GeV/<i>c</i> and pseudorapidity range <span>(|eta ^{gamma }| &lt;0.67)</span>. The isolation selection is based on a charged particle isolation momentum threshold <span>(p_{textrm{T}}^{mathrm{iso,,ch}} = 1.5)</span> GeV/<i>c</i> within a cone of radius <span>(R=0.2)</span>. The associated charged particles are measured in the transverse-momentum ranges <span>(p_{textrm{T}}^{textrm{h}} &gt; 1.8)</span> GeV/<i>c</i> and pseudorapidity <span>(|eta ^{{textrm{h}}}| &lt;0.9)</span>. The yield D(<span>(z_{textrm{T}})</span>) of associated hadrons per trigger, with <span>(z_{textrm{T}} = p_{textrm{T}}^{{textrm{h}}}/p_{textrm{T}}^{gamma })</span>, is measured in three Pb–Pb collision centrality classes: central (0–30%), semicentral (30–50%), and peripheral (50–90%). The D(<span>(z_{textrm{T}})</span>) measurement in pp collisions with the same <span>(p_{textrm{T}}^{gamma })</span> interval was too limited statistically, but at a lower <span>(p_{textrm{T}}^{gamma })</span> interval, showing agreement with theoretical predictions. Therefore, an approximation to the standard <span>(I_{textrm{AA}})</span> is computed from the D(<span>(z_{textrm{T}})</span>) conditional yields, using NLO pQCD predictions as pp reference, the <span>(I_{textrm{pQCD}})</span>. A strong suppression of this ratio is observed in central collisions compared to peripheral collisions. The result extends to a lower <span>(p_{textrm{T}}^{gamma })</span> relative to those reported in previously published Pb–Pb collisions measurements at <span>(sqrt{s_{textrm{NN}}}~=~5.02)</span> TeV. The <span>(I_{textrm{pQCD}})</span> measurement is compared to <span>(I_{textrm{AA}})</span> calculations with an NLO pQCD model that includes energy loss, and to the CoLBT-hydro model. The <span>(I_{textrm{pQCD}})</span> results from central collisions are also compared with <span>(I_{textrm{AA}})</span> measurements of jets correlated with isolated-prompt photons and of hadrons correlated with <span>(hbox {Z}^{0})</span> bosons, both reported by the CMS Collaboration at the LHC, as well as with direct photon–hadron correlation <span>(I_{textrm{AA}})</span> measurements reported by the PHENIX and STAR Collaborations at RHIC. \u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 9","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-16192-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132593","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}

{"title":"Interplay between electroweak symmetry breaking and Higgs portal dark matter","authors":"Sreemanti Chakraborti,&nbsp;André Milagre,&nbsp;Rui Santos,&nbsp;João P. Silva","doi":"10.1140/epjc/s10052-026-16295-7","DOIUrl":"10.1140/epjc/s10052-026-16295-7","url":null,"abstract":"<div><p>Models of Dark Matter must contend with the fact that the presence of electroweak symmetry breaking along the thermal evolution of the Universe modifies the masses, interactions and, thus, the thermally averaged cross sections. We study in detail the impact of taking (not taking) the presence of the electroweak symmetry breaking into account in the calculations of the Dark Matter relic density in Higgs portal models, providing a model-independent measure of such differences. By focusing on a particular model, we show that ignoring this effect can lead to the inclusion (exclusion) of wrong (viable) regions of parameter space.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 9","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-16295-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132595","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}

{"title":"Gluing different gravitational models: f(R) case","authors":"Amin Aalipour,&nbsp;Nima Khosravi","doi":"10.1140/epjc/s10052-026-16336-1","DOIUrl":"10.1140/epjc/s10052-026-16336-1","url":null,"abstract":"<div><p>This paper presents a comprehensive analysis of junction conditions for gluing different <i>f</i>(<i>R</i>) gravitational theories across a non-null hypersurface. Using the variational approach, we systematically derive the junction conditions for both general <i>f</i>(<i>R</i>) theories and the special case of Einstein gravity, for comparison. We demonstrate that when joining two distinct <i>f</i>(<i>R</i>) theories, the junction conditions require continuity of <span>(partial f(R)/partial R)</span>, the extrinsic curvature <span>(K_{mu nu })</span>, while allowing for discontinuities in the Ricci Scalar <i>R</i>. Furthermore, we establish the equivalence between Jordan and Einstein frame formulations through careful treatment of conformal transformations; Our results reveal that different <i>f</i>(<i>R</i>) theories can be consistently matched provided specific relations between their functional forms and geometric quantities are satisfied at the interface.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 9","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-16336-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132589","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}

{"title":"Effective metric for bound state in an effective-one-body theory based on the third-post-Minkowskian approximation","authors":"Hanjun Zou,&nbsp;Sheng Long,&nbsp;Xiaokai He,&nbsp;Zhoujian Cao","doi":"10.1140/epjc/s10052-026-16354-z","DOIUrl":"10.1140/epjc/s10052-026-16354-z","url":null,"abstract":"<div><p>The effective-one-body (EOB) framework, originally formulated within the post-Newtonian (PN) expansion, is central to modeling and interpreting gravitational-wave signals. Recent developments have incorporated the post-Minkowskian (PM) expansion into EOB theory. In this work, we focus on the bound state dynamics in the PM approximation up to the third order and construct the core ingredients of EOB: the effective metric. We examine two correspondence strategies, one based on the radial action variable and the other on the precession angle. We demonstrate that the radial action variable provides a consistent correspondence, which is further verified by the correspondence based on the precession angle. Building on these results, we adopt an isotropic gauge with a Schwarzschild-like parametrization to fix the remaining freedom. Within this parametrization, the effective metric coefficients are determined at 3PM order. Our results provide a consistent effective metric for the bound state dynamics.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 9","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-16354-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132591","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}

{"title":"Exploring the effects of color reconnection on net-charge fluctuations in pp collisions at (sqrt{s}=2.76 text { TeV}) using PYTHIA Monash","authors":"Dibakar Dhar,&nbsp;Tumpa Biswas,&nbsp;Zubayer Ahammed,&nbsp;Prabir Kumar Haldar","doi":"10.1140/epjc/s10052-026-16397-2","DOIUrl":"10.1140/epjc/s10052-026-16397-2","url":null,"abstract":"<div><p>This work explores the effects of various color reconnection (CR) configurations on the net charge fluctuations of charged particles generated in <i>pp</i> collisions at a center-of-mass energy of <span>(sqrt{s})</span> = 2.76 TeV, simulated with the PYTHIA Monash using the variable <span>(nu _{(+,-,text {dyn})})</span>. The results are compared with experimental data from ALICE, revealing that the current PYTHIA simulation settings overestimate the net charge fluctuations relative to the experimental observations. Furthermore, <span>(nu _{(+,-,text {dyn})})</span> exhibits a clear dependence on the MPICR range parameter, where increasing the range leads to more negative <span>(nu _{(+,-,text {dyn})})</span> values, suggesting the geometric extent of CR directly modulates the strength of local charge correlation. To ensure these effects are not a trivial consequence of particle density, a comparison with a retuned NoCR baseline at fixed multiplicity was performed. This analysis confirms that CR induces a genuine dynamical shift in fluctuations that persists independently of the average charged-particle density. The study also shows that the net charge and net pion channels display the strongest suppression in <span>(langle N_{text {ch}} rangle nu _{(+-,text {dyn})})</span> compared to the net kaon and net proton channels. Overall, the study offers a useful benchmark against experimental results and sheds light on the underlying dynamics of the PYTHIA Monash.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 9","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-16397-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149133096","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}