The European Physical Journal C最新文献

{"title":"Resolution of (heavy) primaries in ultra high energy cosmic rays","authors":"Blaž Bortolato,&nbsp;Jernej F. Kamenik,&nbsp;Michele Tammaro","doi":"10.1140/epjc/s10052-024-13663-z","DOIUrl":"10.1140/epjc/s10052-024-13663-z","url":null,"abstract":"<div><p>Measurements of ultra-high energy cosmic rays (UHECR) suggest a complex composition with significant contributions from heavy nuclei at the highest energies. We systematically explore how the selection and number of primary nuclei included in the analysis impact the inferred UHECR mass composition. Introducing a distance measure in the space of <span>(X_textrm{max})</span> distribution moments, we demonstrate that limiting the analysis to a few primaries can introduce significant biases, particularly as observational data improves. We provide lists of primaries approximately equidistant in the new measure, which guaranty unbiased results at given statistical confidence. Additionally, we explore consistent inclusion of nuclei heavier than iron and up to plutonium, deriving first observational upper bounds on their contributions to UHECR with the Pierre Auger Open Data.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"84 12","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-024-13663-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142844743","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":"Screening length of a heavy quark–antiquark pair in non-commutative plasma","authors":"Ping-ping Wu,&nbsp;Xiangrong Zhu,&nbsp;Zi-qiang Zhang","doi":"10.1140/epjc/s10052-024-13646-0","DOIUrl":"10.1140/epjc/s10052-024-13646-0","url":null,"abstract":"<div><p>We investigate the screening length of a heavy quark–antiquark (<span>(Q{bar{Q}})</span>) pair in non-commutative <span>({mathcal {N}}=4)</span> super Yang–Mills plasma at strong coupling. We perform the analysis by computing the Wilson loop in a boosted background and consider the axis of the <span>(Q{bar{Q}})</span> pair along different directions. It turns out that the inclusion of non-commutativity increases the screening length, thus enhancing the binding energy of the <span>(Q{bar{Q}})</span> pair. Furthermore, the presence of non-commutativity reduces quarkonium dissociation, in agreement with previous findings of the imaginary potential and entropic force.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"84 12","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-024-13646-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142844742","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":"Thermalization and non-monotonic entanglement growth in an exactly solvable model","authors":"Shruti Paranjape,&nbsp;Nilakash Sorokhaibam","doi":"10.1140/epjc/s10052-024-13678-6","DOIUrl":"10.1140/epjc/s10052-024-13678-6","url":null,"abstract":"<div><p>We study quantum quenches and subsequent non-equilibrium dynamics of free Dirac fermions in 1 + 1 spacetime dimensions using time dependent mass. The final state is a normalized boundary state which is called generalized Calabrese-Cardy (gCC) state and the system thermalizes to a generalized Gibb’s Ensemble(GGE). We can also tune the initial states so that the final states are exact Calabrese-Cardy (CC) state and special gCC states. The system in the CC state thermalizes to a Gibb’s ensemble. We derive closed-form analytic expressions for the growth of entanglement entropy of subsystems consisting of arbitrary number of disjoint intervals in CC state. We show that the entanglement entropy of a single interval grows monotonically before saturation. In case of certain gCC states, for particular charges, the entanglement entropy of a single interval grows non-monotonically when the effective chemical potential is increased beyond a critical value. We argue that the non-monotonic growth of entanglement entropy is a boundary effect which arises due to increase in long range correlation and decrease in short range correlation at early times.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"84 12","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-024-13678-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142844744","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":"Publisher Erratum: Matter-geometry interplay in new scalar tensor theories of gravity","authors":"Mihai Marciu","doi":"10.1140/epjc/s10052-024-13674-w","DOIUrl":"10.1140/epjc/s10052-024-13674-w","url":null,"abstract":"","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"84 12","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-024-13674-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142811261","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":"Charm fragmentation fractions and (mathbf {coverline{c}}) cross section in p–Pb collisions at (mathbf {sqrt{s _{NN}}=5.02 TeV})","authors":"ALICE Collaboration","doi":"10.1140/epjc/s10052-024-13394-1","DOIUrl":"10.1140/epjc/s10052-024-13394-1","url":null,"abstract":"<div><p>The total charm-quark production cross section per unit of rapidity <span>(textrm{d}sigma ({{textrm{c}}overline{textrm{c}}})/textrm{d}y)</span>, and the fragmentation fractions of charm quarks to different charm-hadron species <span>(f(textrm{c}rightarrow {textrm{h}}_{textrm{c}}))</span>, are measured for the first time in p–Pb collisions at <span>(sqrt{s_textrm{NN}} = 5.02~text {Te}hspace{-1.00006pt}textrm{V} )</span> at midrapidity (<span>(-0.96&lt;y&lt;0.04)</span> in the centre-of-mass frame) using data collected by ALICE at the CERN LHC. The results are obtained based on all the available measurements of prompt production of ground-state charm-hadron species: <span>(textrm{D}^{0})</span>, <span>(textrm{D}^{+})</span>, <span>(textrm{D}_textrm{s}^{+})</span>, and <span>(mathrm {J/psi })</span> mesons, and <span>(Lambda _textrm{c}^{+})</span> and <span>(Xi _textrm{c}^{0})</span> baryons. The resulting cross section is <span>( textrm{d}sigma ({{textrm{c}}overline{textrm{c}}})/textrm{d}y =219.6 pm 6.3;(mathrm {stat.}) {;}_{-11.8}^{+10.5};(mathrm {syst.}) {;}_{-2.9}^{+8.3};(mathrm {extr.})pm 5.4;(textrm{BR})pm 4.6;(mathrm {lumi.}) pm 19.5;(text {rapidity shape})+15.0;(Omega _textrm{c}^{0});textrm{mb} )</span>, which is consistent with a binary scaling of pQCD calculations from pp collisions. The measured fragmentation fractions are compatible with those measured in pp collisions at <span>(sqrt{s} = 5.02)</span> and 13 TeV, showing an increase in the relative production rates of charm baryons with respect to charm mesons in pp and p–Pb collisions compared with <span>(mathrm {e^{+}e^{-}})</span> and <span>(mathrm {e^{-}p})</span> collisions. The <span>(p_textrm{T})</span>-integrated nuclear modification factor of charm quarks, <span>(R_textrm{pPb}({textrm{c}}overline{textrm{c}})= 0.91 pm 0.04;mathrm{(stat.)} ^{+0.08}_{-0.09};mathrm{(syst.)} ^{+0.05}_{-0.03};mathrm{(extr.)} pm 0.03;mathrm{(lumi.)})</span>, is found to be consistent with unity and with theoretical predictions including nuclear modifications of the parton distribution functions.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"84 12","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-024-13394-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142811269","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":"Quasinormal modes of three ((2+1))-dimensional black holes in string theory, conformal gravity, and Hu–Sawicki F(R) theory via the Heun function","authors":"F. Naderi,&nbsp;A. Rezaei-Aghdam","doi":"10.1140/epjc/s10052-024-13655-z","DOIUrl":"10.1140/epjc/s10052-024-13655-z","url":null,"abstract":"<div><p>We study the propagation of massless fermionic fields, implementing a family of special functions: Heun functions, in solving the wave equation in three three-dimensional backgrounds, including the BTZ black hole in string theory and Lifshitz black hole solutions in conformal gravity and Hu–Sawicki <i>F</i>(<i>R</i>) theory. The main properties of the selected black hole solutions is that their line elements are Weyl related to that of a homogeneous spacetime, whose spatial part possesses Lie symmetry, described by Lobachevsky-type geometry with arbitrary negative Gaussian curvature. Using the Weyl symmetry of massless Dirac action, we consider the perturbation equations of fermionic fields in relation to those of the homogeneous background, which having definite singularities, are transformed into Heun’s equation. We point out the existence of quasinormal modes labeled by the accessory parameter of the Heun function. The distribution of the quasinormal modes has been clarified to satisfy the boundary conditions that require ingoing and decaying waves at the event horizon and conformal infinity, respectively. It turned out that the procedure based on the Heun function, beside reproducing the previously known results obtained via hypergeometric function for the BTZ and Lifshitz black hole solution in conformal gravity, brings up new families of quasinormal frequencies, which can also contain purely imaginary modes. Also, the analysis of the quasinormal modes shows that with the negative imaginary part of complex frequencies <span>(omega =omega _{Re}+iomega _{Im})</span>, the fermionic perturbations are stable in this background.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"84 12","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-024-13655-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142811151","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":"Collider imprint of vector-like leptons in light of anomalous magnetic moment and neutrino data","authors":"Parham Dehghani,&nbsp;Mariana Frank,&nbsp;Benjamin Fuks","doi":"10.1140/epjc/s10052-024-13659-9","DOIUrl":"10.1140/epjc/s10052-024-13659-9","url":null,"abstract":"<div><p>We investigate the impact of incorporating vector-like leptons into the Standard Model, aiming to address longstanding puzzles related to the anomalous magnetic moments of the muon and electron while maintaining consistency with neutrino masses and mixings. We find that among the various representations of vector-like leptons permitted by the Standard Model gauge symmetry, only weak doublets and singlets offer satisfactory solutions, all associated with a significantly constrained parameter space. Our analysis delves into the associated parameter space, identifying representative benchmark scenarios suitable for collider studies. These setups yield a distinctive six-lepton signature whose associated signals can easily be distinguished from the Standard Model background, providing a clear signal indicative of new physics models featuring vector-like leptons. Our work hence sheds light on the potential implications of vector-like leptons in resolving discrepancies inherent to the Standard Model, while also offering insights into experimental avenues for further exploration.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"84 12","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-024-13659-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142811152","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":"The cosmic timeline implied by the highest redshift quasars","authors":"Fulvio Melia","doi":"10.1140/epjc/s10052-024-13652-2","DOIUrl":"10.1140/epjc/s10052-024-13652-2","url":null,"abstract":"<div><p>The conventional picture of supermassive black-hole growth in the standard model had already been seriously challenged by the emergence of <span>(sim 10^9;M_odot )</span> quasars at <span>(zsim 7.5)</span>, conflicting with the predicted formation of structure in the early <span>(varLambda )</span>CDM Universe. But the most recent <i>JWST</i> discovery of a <span>(sim 10^8;M_odot )</span> source at <span>(zsim 10.1)</span> argues even more strongly against the possibility that these black holes were created in Pop II or III supernovae, followed by Eddington-limited accretion. Attempts at resolving this anomaly have largely focused on the formation of seeds via an exotic, direct collapse of primordial gas to an initial mass <span>(sim 10^5;M_odot )</span> – a process that has never been seen anywhere in the cosmos. Our goal in this <i>Letter</i> is to demonstrate that the emergence of these black holes is instead fully consistent with standard astrophysics in the context of the alternative Friedmann–Lemaître–Robertson–Walker cosmology known as the <span>(R_textrm{h}=ct)</span> universe. We show that, while the predicted evolution in the standard model is overly compressed, the creation, growth and appearance of such high-<i>z</i> quasars fall comfortably within the evolutionary history in this cosmology, thereby adding considerable observational support to the existing body of evidence favoring it over the standard scenario.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"84 12","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-024-13652-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142798368","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":"The QED nonfactorizable correction to the semileptonic charmed three-body B decays","authors":"Yueling Yang,&nbsp;Liting Wang,&nbsp;Jiazhi Li,&nbsp;Qin Chang,&nbsp;Junfeng Sun","doi":"10.1140/epjc/s10052-024-13647-z","DOIUrl":"10.1140/epjc/s10052-024-13647-z","url":null,"abstract":"<div><p>In this paper, the nonfactorizable photonic corrections to the effective four-fermion vertex for the <span>(overline{B})</span> <span>({rightarrow })</span> <span>(D^{({*})})</span> <span>(+)</span> <span>({ell }^{-})</span> <span>(+)</span> <span>(bar{nu }_{ell })</span> decays are considered at the quark level within SM, where <span>({ell })</span> <span>(=)</span> <i>e</i>, <span>({mu })</span> and <span>({tau })</span>. It is found that the QED corrections are closely related with the mass of the charged lepton. The QED contributions will enhance branching ratios, which results in the slight reduction of ratios <span>(R(D^{(*)}))</span> and the relationship <span>(R(D^{(*)})_{e})</span> &lt; <span>(R(D^{(*)})_{mu })</span>.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"84 12","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-024-13647-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142798480","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":"Anomaly induced inflation in the minimal quartic extension of Einstein’s gravity","authors":"Kerim Demirel,&nbsp;Bayram Tekin","doi":"10.1140/epjc/s10052-024-13611-x","DOIUrl":"10.1140/epjc/s10052-024-13611-x","url":null,"abstract":"<div><p>A particular extension of Einstein’s General Relativity up to and including quartic terms in the curvature tensor is minimal in the sense that it has a unique maximally symmetric vacuum and only a massless spin-2 excitation in its spectrum around the vacuum. We study the inflation phase of the universe in this minimal quartic extension of Einstein’s gravity in the presence of trace anomaly terms coming from the Standard Model fields and the fields of the Minimal Supersymmetric Standard Model. We show that the theory allows a quasi-de Sitter phase with sufficient <i>e</i>-foldings.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"84 12","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-024-13611-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142798467","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}