The European Physical Journal C最新文献

The Regge–Gribov model of the pomeron and odderon in non-trivial transverse space is studied by the renormalization group technique in the single-loop approximation. The pomeron and odderon are taken to have different bare intercepts and slopes. The behaviour when the intercepts move from below to their critical values compatible with the Froissart limitation is studied. The singularities in the form of non-trivial branch points indicating a phase transition are found in the vicinity of five fixed points reported in a previous publication. Since new phases violate the projectile–target symmetry, the model is found non-physical for the bare intercepts above their critical value.

We perform an analysis of the scalar sector of 3 Higgs Doublet Models with softly broken (Delta (54)) and (Sigma (36)) symmetries. We consider the various vacuum expectation value alignments and consider, for each, softly broken terms that deviate the alignment. We check the evolution of the minima, present analytical and numerical results for the lifting of the degeneracies of the physical eigenstates, and describe the decays of the states considering any residual symmetries.

Motivated by the recent developments in the thermodynamics of Taub–NUT spaces and the absence of Misner strings in Taub–NUT solutions with flat horizons, we study the phase structure of the dyonic Taub–NUT solutions with Lorentzian signature. We follow the treatment proposed in arXiv:2206.09124 and arXiv:2304.06705 to introduce the NUT parameter as a conserved charge to the first law. Although the calculated quantities satisfy the first law, we have found a larger class of charges that satisfy the first law and depend on some arbitrary parameter (alpha ). We choose to describe phase diagrams as NUT parameter-temperature graphs to show borders of big and small black brane phases. We study the phase structure of these spaces in a mixed ensemble (i.e., fixed electric potential, NUT charge, and magnetic charge), which we classify into different cases depending on the value of (alpha ) and the other quantities. Most of these cases not only have first-order phase transitions, but also, end at critical points. Some of these cases include up to four critical points, depending on the value of (alpha ) and the other quantities.

In recent works (M.D. Piano, S. Hohenegger, F. Sannino, Quantum black hole physics from the event horizon. Phys. Rev. D 109(2), 024045 (2024). https://doi.org/10.1103/PhysRevD.109.024045. arXiv:2307.13489 [gr-qc], M.D. Piano, S. Hohenegger, F. Sannino, Effective metric descriptions of quantum black holes. Eur. Phys. J. C 84(12), 1273 (2024). https://doi.org/10.1140/epjc/s10052-024-13609-5. arXiv:2403.12679 [gr-qc]), a framework has been developed to describe (quantum) deformed, spherically symmetric and static black holes in four dimensions. The key idea of this so-called Effective Metric Description (EMD) is to parametrise deformations of the classical Schwarzschild geometry by two functions that depend on a physical quantity and which are calculated in a self-consistent way as series expansions in the vicinity of the horizon. In this work we further strengthen this framework by first demonstrating that the corresponding series expansion coefficients can be completely and uniquely determined from measurements that are accessible for observers outside of the event horizon: we propose a Gedankenexperiment, consisting of probes following a free-falling trajectory that send signals to a stationary observer and show how an EMD can be constructed from suitable telemetric data. Furthermore, by linking the expansion coefficients of the EMD to the invariant eigenvalues of the energy momentum tensor, we determine a system of physical fields that provides an effective Einstein equation for the deformed black hole geometry. In the case of a simplified geometry and assuming that the metric deformations are small, we can write the leading order of the physical fields in a closed form in the metric functions. We illustrate our results at the example of the Hayward space-time.

Bayesian analysis results require a choice of prior distribution. In long-baseline neutrino oscillation physics, the usual parameterisation of the mixing matrix induces a prior that privileges certain neutrino mass and flavour state symmetries. Here we study the effect of privileging alternate symmetries on the results of the T2K experiment. We find that constraints on the level of CP violation (as given by the Jarlskog invariant) are robust under the choices of prior considered in the analysis. On the other hand, the degree of octant preference for the atmospheric angle depends on which symmetry has been privileged.

Motivated by integrating the dilaton field (as a UV correction) with dRGT-like massive gravity (as an IR correction) into Einstein gravity, we investigate the thermodynamic and optical properties of black holes within this gravitational framework. We begin by reviewing the black hole solutions in Maxwell–dilaton–dRGT-like massive gravity, followed by an analysis of how various parameters influence on the asymptotical behavior of the spacetime and the event horizon of these black holes. In the subsequent section, we examine the conserved and thermodynamic quantities associated with these black holes, paying particular attention to the effects of parameters like (beta ,) (alpha ,) and the massive parameters ((eta _{1}) and (eta _{2})) on their local stability by simultaneously evaluating the heat capacity and temperature. We also adopt an alternative method to study phase transitions using geometrothermodynamics. Furthermore, we explore how the parameters of Maxwell–dilaton–dRGT-like massive gravity impacts the optical characteristics and radiative behavior of black holes. In particular, we analyze the effects of the dilaton coupling constant ((alpha ),) charge (q),  the massive gravity parameter ((eta _1),) and the graviton mass ((m_g)) on the radius of the photon sphere and the resulting black hole shadow. Moreover, the theoretical shadow radius is compared to the observational data from (Sgr A^*.) Additionally, we investigate the energy emission rate of these black holes, revealing that these parameters substantially influence the emission peak.

This paper presents the measurement of the isolated prompt photon inclusive production cross section in pp and p–Pb collisions by the ALICE Collaboration at the LHC. The measurement is performed in p–Pb collisions at centre-of-mass energies per nucleon pair of (sqrt{s_{text {NN}}}={5.02},textrm{TeV}) and 8.16 TeV, as well as in pp collisions at (sqrt{s}={5.02},textrm{TeV}) and 8 TeV. The cross section is obtained at midrapidity ((|y|<0.7)) using a charged-track based isolation momentum (p_textrm{T}^{text {iso,~ch}}<{1.5},textrm{GeV}/c) in a cone with radius (R=0.4). The data for both collision systems are well reproduced by perturbative QCD (pQCD) calculations at next-to-leading order (NLO) using recent parton distribution functions for free (PDF) and bound (nPDF) nucleons. Furthermore, the nuclear modification factor (R_{text {pA}}) for both collision energies is consistent with unity for (p_{textrm{T}}) (>{20},textrm{GeV}/c). However, deviations from unity ((R_textrm{pA}<1)) of up to 20% are observed for (p_{textrm{T}}) (<{20},textrm{GeV}/c) with limited significance, indicating the possible presence of nuclear effects in the initial state of the collision. The suppression increases with decreasing (p_{textrm{T}}) with a significance of (2.3upsigma ) for a non-zero slope and yields (R_{textrm{pA}}<1) with a significance of (1.8upsigma ) at (sqrt{s_{textrm{NN}}}={8.16},textrm{TeV}) for (p_{textrm{T}}) (<{20},textrm{GeV}/c). In addition, a significance of (1.1upsigma ) is observed for (R_{textrm{pA}}<1) at the lower collision energy (sqrt{s_{textrm{NN}}}={5.02},textrm{TeV}) for (p_{textrm{T}} < {14},textrm{GeV}/c). The magnitude and shape of the suppression are consistent with pQCD predictions at NLO using nPDFs that incorporate nuclear shadowing effects in the Pb nucleus.

We systematically investigated the limited inverse discrete Fourier transform of the quasi distributions from the perspective of inverse problem theory. This transformation satisfies two of Hadamard’s well-posedness criteria, existence and uniqueness of solutions, but critically violates the stability requirement, exhibiting exponential sensitivity to input perturbations. To address this instability, we implemented Tikhonov regularization with L-curve optimized parameters, demonstrating its validity for controlled toy model studies and real lattice QCD results of quasi distribution amplitudes. The reconstructed solutions is consistent with the physics-driven (lambda )-extrapolation method. Our analysis demonstrates that the inverse Fourier problem within the large-momentum effective theory (LaMET) framework belongs to a class of moderately tractable ill-posed problems, characterized by distinct spectral properties that differ from those of more severely unstable inverse problems encountered in other lattice QCD applications. Tikhonov regularization establishes a rigorous mathematical framework for addressing the underlying instability, enabling first-principles uncertainty quantification without relying on ansatz-based assumptions.

As an extension of the previous work on Solar System tests of an effective loop quantum black hole, and an attempt to find more stringent constraints on the loop quantum effect, we study its effects on physical experiments and astronomical observations conducted in the Solar System. By considering light deflection, time delay, and Cassini tracking experiments at the second post-Newtonian (2PN) order for light propagation, we find that the parametrized post-Newtonian (PPN) parameter (gamma ) in the black hole strictly equals 1. Using supplementary advances for Mercury taken from the EPM2011 and INPOP10a ephemerides, we derive much improved bounds on the black hole, which strengthen constraints on the loop quantum effect by ten times. Since such quantum effects are more likely to be observable in strong-field regimes, we estimate a preliminary bound on the loop quantum effect in these regimes based on results from EHT observations, discuss future prospects of other tests (e.g., extreme mass-ratio inspiral systems), and compare these strong-field constraints with those from the Solar System. It is worth noting that primordial black holes might provide a promising way to identify the loop quantum effect. Solar system experiments are probably not applicable for probing the quantum effect signal.

We report a feasibility study of the hyperon semileptonic decay (varLambda rightarrow pe^{-} {bar{nu }}_{e}) by using a fast simulation software package at STCF. With an anticipated integrated luminosity of 3.4 trillion (J/psi ) per year at a center-of-mass energy of 3.097 GeV, the statistical sensitivity of the branching fraction is determined to be 0.15%. The statistical sensitivities of form factors (g_{av}) and (g_w) are determined to be 0.4% and 2.15%, respectively. The projected sensitivity of (|V_{us}|) is obtained by combining this result with (g_1(0)) from Lattice QCD, to be 0.9%, including the systematic uncertainty from the LQCD input and the statistical uncertainties of input branching fraction and form factors. The precise measurement to be obtained at STCF will provide a rigorous test of the Standard Model.