D. Barducci, D. Germani, M. Nardecchia, S. Scacco, C. Toni
{"title":"On the Atomki nuclear anomaly after the MEG-II result","authors":"D. Barducci, D. Germani, M. Nardecchia, S. Scacco, C. Toni","doi":"10.1007/JHEP04(2025)035","DOIUrl":"10.1007/JHEP04(2025)035","url":null,"abstract":"<p>Recent experimental results from the Atomki collaboration have reported the observation of anomalous effects in Beryllium, Helium and Carbon nuclear transitions that could hint at physics beyond the Standard Model. However, the MEG-II experiment has recently found no significant anomalous signal in the Beryllium transition <sup>8</sup>Be<sup>⋆</sup> → <sup>8</sup>Be + <i>e</i><sup>+</sup><i>e</i><sup>−</sup>. In view of this result, we critically re-examine the possible theoretical interpretations of the anomalies observed by the Atomki experiment in terms of a new boson <i>X</i> with mass around 17 MeV. The present work aims to study the phenomenology of a spin-2 state and revisit the possibility of a pure CP-even scalar, which was initially dismissed due to its inability to explain the Beryllium anomalous signal. Our analysis shows that a spin-2 state is highly disfavoured by the SINDRUM constraint while a scalar boson could explain the Helium and Carbon anomalies while being compatible with other experimental constraints.</p>","PeriodicalId":635,"journal":{"name":"Journal of High Energy Physics","volume":"2025 4","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/JHEP04(2025)035.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Modular invariant Starobinsky inflation and the Species Scale","authors":"Gonzalo F. Casas, Luis E. Ibáñez","doi":"10.1007/JHEP04(2025)041","DOIUrl":"10.1007/JHEP04(2025)041","url":null,"abstract":"<p>Potentials in cosmological inflation often involve scalars with trans-Planckian ranges. As a result, towers of states become massless and their presence pushes the fundamental scale not to coincide with <i>M</i><sub>P</sub> but rather with the <i>species scale</i>, Λ. This scale transforms as an automorphic form of the theory’s duality symmetries. We propose that the inflaton potential should be 1) an automorphic invariant form, non-singular over all moduli space, 2) depending only on Λ and its field derivatives, and 3) approaching constant values in the region of large moduli VEVs to ensure a long period of inflation. These conditions lead to the proposal <i>V</i> ~ <i>λ</i>(<i>ϕ, ϕ</i><sup>*</sup>), with <span>( lambda ={G}^{ioverline{j}}left({partial}_iLambda right)left({partial}_{overline{j}}Lambda right)/{Lambda}^2 )</span>, determining the ‘species scale convex hull’. For a single elliptic complex modulus with SL(2<i>, Z</i>) symmetry, this results in an inflaton potential <span>( Vsimeq {left(operatorname{Im}tau right)}^2{left|{overset{sim }{G}}_2right|}^2/{N}^2 )</span>, with <i>N</i> ≃ − log(Im<i>τ</i>|<i>η</i>(<i>τ</i>)|<sup>4</sup>), where <i>η</i> is the Dedekind function and <span>( {overset{sim }{G}}_2 )</span> the Eisenstein modular form of weight 2. Surprisingly, this potential at large modulus VEV resembles that of the Starobinsky model. We compute inflationary parameters yielding results similar to Starobinsky’s, but extended to modular invariant expressions. Interestingly, the number of e-folds is proportional to the number of species in the tower, <i>N</i><sub><i>e</i></sub> ≃ <i>N</i>, and <i>ϵ</i> ≃ Λ<sup>4</sup> at large moduli VEV, suggesting that the tower of states plays an important role in the inflation process.</p>","PeriodicalId":635,"journal":{"name":"Journal of High Energy Physics","volume":"2025 4","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/JHEP04(2025)041.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
Sébastien Reymond, Mario Trigiante, Thomas Van Riet
{"title":"Supergravity solutions for Dp-D(6 − p) bound states: from p = 7 to p = −1","authors":"Sébastien Reymond, Mario Trigiante, Thomas Van Riet","doi":"10.1007/JHEP04(2025)037","DOIUrl":"10.1007/JHEP04(2025)037","url":null,"abstract":"<p>Near horizon geometries of D<i>p</i>-branes with <i>p</i> ≠ 3 are singular with a running dilaton. Bound states of D<i>p</i> branes with their magnetic cousins, D(6 − <i>p</i>) branes, can stabilise the dilaton such that an AdS factor might appear in the near horizon region, potentially leading to a chain of AdS vacua of the form <i>AdS</i><sub><i>p</i>+2</sub> × <i>S</i><sup><i>p</i>+2</sup> × 𝕋<sup>6<i>−</i>2<i>p</i></sup>. The solutions with <i>p</i> = −1, 1, 3 are supersymmetric with the cases <i>p</i> = 1, 3 being well-known examples already. We construct explicit (partially smeared) brane bound state solutions for all such configurations. The D2-D4 and D(−1)-D7 cases are entirely novel, but they do not have a near-horizon AdS geometry. The two novel classes of solutions feature ghost branes (negative tension branes), and we suggest they are physical for the D(−1)-D7 solutions but unphysical for the D2-D4 solutions. The bound state of a D(−1) and a D7 brane in supergravity was only hinted upon recently in [1]. We correct the solution here in order to preserve supersymmetry, and find that the dilaton can indeed be stabilized. This points to a possible dual matrix theory, generalizing the IKKT matrix model to allow for conformal invariance.</p>","PeriodicalId":635,"journal":{"name":"Journal of High Energy Physics","volume":"2025 4","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/JHEP04(2025)037.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"No-quenching baseline for energy loss signals in oxygen-oxygen collisions","authors":"Jannis Gebhard, Aleksas Mazeliauskas, Adam Takacs","doi":"10.1007/JHEP04(2025)034","DOIUrl":"10.1007/JHEP04(2025)034","url":null,"abstract":"<p>In this work, we perform computations of inclusive jet, and semi-inclusive jet-hadron cross sections for minimum bias oxygen-oxygen collisions at RHIC and LHC collision energies. We compute the no-quenching baseline for the jet nuclear modification factor <i>R</i><sub>AA</sub> and jet-, and hadron-triggered semi-inclusive nuclear modification factors <i>I</i><sub>AA</sub>. We do this with state-of-the-art nuclear parton distribution functions (nPDFs), next-to-leading-order matrix elements, parton shower, and hadronization. We observe deviations from unity due to cold-nuclear matter effects, even without quenching. We demonstrate that the parton distribution uncertainties constitute a significant obstacle in detecting energy loss in small collision systems. Hadron-triggered observables are particularly sensitive to uncertainties due to correlations between the trigger and analyzed particles. For jet-triggered <i>I</i><sub>AA</sub>, there exists a kinematic window in which nPDF and scale uncertainties cancel dramatically while showing little sensitivity to parton shower and hadronization models, addressing a major limiting factor for energy loss discovery in small systems.</p>","PeriodicalId":635,"journal":{"name":"Journal of High Energy Physics","volume":"2025 4","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/JHEP04(2025)034.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Closed string amplitudes around tachyon vacuum solution in Kaku theory","authors":"Yuji Ando","doi":"10.1007/JHEP04(2025)029","DOIUrl":"10.1007/JHEP04(2025)029","url":null,"abstract":"<p>We incorporate closed string field into Kaku’s open string field theory which is defined using Kaku vertex, and we construct open-closed string field theory. To do this, we define new consistent open-closed vertex and open-open-closed vertex with the Kaku vertex. Because these vertices depend on Chan-Paton parameter such as the Kaku vertex, the open-closed string field theory action that we construct depends on the Chan-Paton parameter such as the Kaku’s theory action. However, we can show that an infinitesimal change in <i>l</i> corresponds to a field redefinition. Furthermore, we compute closed string amplitudes around tachyon vacuum solution in this theory. As a result, we confirm that these amplitudes are conventional pure closed string amplitudes on surfaces without boundaries.</p>","PeriodicalId":635,"journal":{"name":"Journal of High Energy Physics","volume":"2025 4","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/JHEP04(2025)029.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Spectral projections for density matrices in quantum field theories","authors":"Wu-zhong Guo","doi":"10.1007/JHEP04(2025)033","DOIUrl":"10.1007/JHEP04(2025)033","url":null,"abstract":"<p>In this paper, we investigate the spectral projection of density matrices in quantum field theory. With appropriate regularization, the spectral projectors of density matrices are expected to be well-defined. These projectors can be obtained using the Riesz projection formula, which allows us to compute both the density of eigenvalues and the expectation values of local operators in the projected states. We find that there are universal divergent terms in the expectation value of the stress energy tensor, where the coefficients depend universally on the density of eigenvalues and a function that describes the dependence of eigenvalues on boundary location. Using projection states, we can construct a series of new states in quantum field theories and discuss their general properties, focusing on the holographic aspects. We observe that quantum fluctuations are suppressed in the semiclassical limit. We also demonstrate that the fixed area state, previously constructed using gravitational path integrals, can be constructed by suitably superposition of appromiate amount of projection states. Additionally, we apply spectral projection to non-Hermitian operators, such as transition matrices, to obtain their eigenvalues and densities. Finally, we highlight potential applications of spectral projections, including the construction of new density and transition matrices and the understanding of superpositions of geometric states.</p>","PeriodicalId":635,"journal":{"name":"Journal of High Energy Physics","volume":"2025 4","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/JHEP04(2025)033.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"A new approach to superstring","authors":"A. Schwarz","doi":"10.1007/JHEP04(2025)021","DOIUrl":"10.1007/JHEP04(2025)021","url":null,"abstract":"<p>We show how starting with one-string space of states in BRST formalism one can construct a large class of physical quantities containing, in particular, scattering amplitudes for bosonic string and superstring. The same techniques work for heterotic string.</p>","PeriodicalId":635,"journal":{"name":"Journal of High Energy Physics","volume":"2025 4","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/JHEP04(2025)021.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Variational Loop Vertex Expansion","authors":"Vasily Sazonov","doi":"10.1007/JHEP04(2025)032","DOIUrl":"10.1007/JHEP04(2025)032","url":null,"abstract":"<p>Loop Vertex Expansion (LVE) was developed to construct QFT models with local and non-local interactions. Using LVE, one can prove the analyticity in the finite cardioid-like domain in the complex plain of the coupling constant of the free energies and cumulants of various vector, matrix, or tensor-type models. Here, applying the idea of choosing the initial approximation depending on the coupling constant, we construct the analytic continuation of the free energy of the quartic matrix model beyond the standard LVE cardioid over the branch cut and for arbitrary large couplings.</p>","PeriodicalId":635,"journal":{"name":"Journal of High Energy Physics","volume":"2025 4","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/JHEP04(2025)032.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
Krishna Rajagopal, Bruno Scheihing-Hitschfeld, Rachel Steinhorst
{"title":"Adiabatic Hydrodynamization and the emergence of attractors: a unified description of hydrodynamization in kinetic theory","authors":"Krishna Rajagopal, Bruno Scheihing-Hitschfeld, Rachel Steinhorst","doi":"10.1007/JHEP04(2025)028","DOIUrl":"10.1007/JHEP04(2025)028","url":null,"abstract":"<p>“Attractor” solutions for the pre-hydrodynamic, far-from-equilibrium, evolution of the matter produced in relativistic heavy ion collisions have emerged as crucial descriptors of the rapid hydrodynamization of quark-gluon plasma (QGP). Adiabatic Hydrodynamization (AH) has been proposed as a framework with which to describe, explain, and predict attractor behavior that draws upon an analogy to the adiabatic approximation in quantum mechanics. In this work, we systematize the description of pre-hydrodynamic attractors in kinetic theory by showing how to use the AH framework to identify these long-lived solutions to which varied initial conditions rapidly evolve, demonstrating the robustness of this framework. In a simplified QCD kinetic theory in the small-angle scattering limit, we use AH to explain both the early- and late-time scaling behavior of a longitudinally expanding gluon gas in a unified framework. In this context, we show that AH provides a unified description of, and intuition for, all the stages of what in QCD would be bottom-up thermalization, starting from a pre-hydrodynamic attractor and ending with hydrodynamization. We additionally discuss the connection between the notions of scaling behavior and adiabaticity and the crucial role of time-dependent coordinate redefinitions in identifying the degrees of freedom of kinetic theories that give rise to attractor solutions. The tools we present open a path to the intuitive explanation of how attractor behavior arises and how the attractor evolves in all stages of the hydrodynamization of QGP in heavy ion collisions.</p>","PeriodicalId":635,"journal":{"name":"Journal of High Energy Physics","volume":"2025 4","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/JHEP04(2025)028.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Unveiling the invisible: ALPs and sterile neutrinos at the LHC and HL-LHC","authors":"Kingman Cheung, C. J. Ouseph, Sin Kyu Kang","doi":"10.1007/JHEP04(2025)024","DOIUrl":"10.1007/JHEP04(2025)024","url":null,"abstract":"<p>We investigate the potential of using the signature of mono-Higgs plus large missing energies to constrain on two new ph\tysics models, namely the model of an axion-like particle (ALP) and the model of sterile neutrinos. We focus on the Higgs-ALP interactions starting at dimension-six and the Higgs-sterile neutrino interactions starting at dimension-five, via the processes <i>pp</i> → <i>haa</i> for ALP production and <i>pp</i> → <i>hNN</i> for sterile neutrinos at the LHC and High Luminosity LHC (HL-LHC), followed by the Higgs decay <span>( hto boverline{b} )</span>. We establish bounds on the ALP-Higgs coupling <span>( frac{C_{aH}}{Lambda^2} )</span> and sterile neutrino-Higgs coupling <span>( frac{lambda_3}{M_{ast }} )</span>, respectively, for ALP and sterile-neutrino mass ranging from 1 to 60 GeV, using the recent ATLAS data on mono-Higgs plus missing energies at the LHC (<span>( sqrt{s} )</span> = 13 TeV and <span>( mathcal{L} )</span> = 139 fb<sup>−1</sup>). The most stringent constraint occurs in the missing transverse energy <i>M</i><sub><i>ET</i></sub> range 200 < <i>M</i><sub><i>ET</i></sub> ≤ 350 GeV. We also estimate the sensitivities that we can achieve at the HL-LHC (<span>( sqrt{s} )</span> = 14 TeV and <span>( mathcal{L} )</span> = 3000 fb<sup>−1</sup>). We obtain improved sensitivities across various missing energy regions. The ALP model exhibits better sensitivities, particularly at lower mass range, compared to the sterile neutrino model, which shows weaker sensitivities across similar mass and energy ranges. Our results underscore the potential of the mono-Higgs signature as a robust probe for physics beyond the Standard Model.</p>","PeriodicalId":635,"journal":{"name":"Journal of High Energy Physics","volume":"2025 4","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/JHEP04(2025)024.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
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