Journal of High Energy Physics最新文献

One of the key issues in holography is going beyond AdS and defining quantum gravity in spacetimes with a null boundary. Recent examples of this type involve linear dilaton asymptotics and are related to the (Toverline{T }) deformation. We present a holographic correspondence derived from string theory, which is an example of a kind of celestial holography. The holographic definition is a spacetime non-commutative open string theory supported on D1-D5 branes together with fundamental strings. The gravity solutions interpolate between AdS₃ metrics and six-dimensional metrics. Radiation can escape to null infinity, which makes both the encoding of quantum information in the boundary and the dynamics of black holes quite different from AdS spacetimes.

A method for obstructing symmetry enhancement in numerical conformal bootstrap calculations is proposed. Symmetry enhancement refers to situations where bootstrap studies initialised with a certain symmetry end up allowing theories with higher symmetry. In such cases, it is shown that redundant operators in the less symmetric theory can descend from primary scaling operators of the more symmetric one, motivating the imposition of spectral gaps that are justified in the former but not the latter. The same mechanism can also be used to differentiate between decoupled and fully coupled theories which otherwise have the same global symmetry. A systematic understanding of this mechanism is developed and applied to distinguish the cubic from the O(3) model in three dimensions, where a strip of disallowed parameter space, referred to as the cubic redundancy channel, emerges once a gap associated with a redundant operator of the cubic theory is imposed. The channel corresponds precisely to the region of parameter space where the assumed cubic symmetry would be enhanced to O(3).

The amplitudes of the non-linear sigma model can be obtained from those of Tr(Φ³) theory by sending the kinematic (Mandelstam) variables to infinity in a certain direction. In this paper we characterize the behavior of Tr(Φ³) amplitudes under a general class of large kinematic shifts called g-vector shifts. The objects that live in this world at infinity retain certain key amplitude-like properties, most notably factorization, and admit descriptions in terms of polytopes, but they are not generally amplitudes of any cognizable theory. We identify particular g-vector shifts that lead at infinity to mixed amplitudes involving two pions and any number of scalars, allowing us to provide polytopal descriptions of these amplitudes.

We investigate the impact of dark Abelian gauge bosons on the electroweak precision measurements at the one-loop level. The dark gauge boson couples to the standard model fermions generally via two kinds of mixing with the electroweak gauge bosons: the kinetic mixing and the mass mixing. We solve the Schwinger-Dyson equation for the gauge boson propagators and derive a renormalization scheme-independent representation of the scattering amplitudes for four-fermion processes, including the full oblique corrections. We define the running parameters at the one-loop level and show that the leading new physics effects, including the mixing, in the electroweak precision observables can be described by the oblique parameters S, T, and U as in the standard electroweak gauge theory when the new physics scale is sufficiently high and the dark gauge boson mass lies away from the Z pole. We consider the dark doublet scalar boson as an example and numerically show that a novel one-loop effect can drastically change the parameter region allowed by the electroweak precision tests.

We develop a pure spinor worldline formalism for computing tree-level scattering amplitudes in 11D supergravity. Focusing first on the 4-point amplitude, we demonstrate that our prescription is consistent with BRST symmetry and gauge invariance, and that the resulting expression is invariant under permutation of the external particles. Remarkably, the amplitude admits a compact representation in pure spinor superspace and agrees precisely with the result obtained via perturbiner methods. We further extend our construction to the N-point case, proposing a general correlator that preserves BRST closure and gauge invariance, thereby offering a systematic framework for higher-point computations in 11D supergravity.

Semi-holography provides a formulation of dynamics in gauge theories involving both weakly self-interacting (perturbative) and strongly self-interacting (non-perturbative) degrees of freedom. These two subsectors interact via their effective metrics and sources, while the full local energy-momentum tensor is conserved in the physical background metric. In the large N limit, the subsectors have their individual entropy currents, and so the full system can reach a pseudo-equilibrium state in which each subsector has a different physical temperature.

We first complete the proof that the global thermal equilibrium state, where both subsectors have the same physical temperature, can be defined in consistency with the principles of thermodynamics and statistical mechanics. Particularly, we show that the global equilibrium state is the unique state with maximum entropy in the microcanonical ensemble. Furthermore, we show that in the large N limit, a typical non-equilibrium state of the full isolated system relaxes to the global equilibrium state when the average energy density is large compared to the scale set by the inter-system coupling. We discuss quantum statistical perspectives.

We recursively construct tree-level electromagnetic and gravitational Compton amplitudes of higher-spin massive particles by the all-line transverse momentum shift. With three-point amplitude as input, we demonstrate that higher-point electromagnetic and gravitational Compton amplitudes are on-shell constructible up to spin s = 3/2 and s = 5/2, respectively, under the all-line transverse shift after imposing the current constraint condition. We unambiguously derive the four-point electromagnetic and gravitational Compton amplitudes for s ≤ 3/2 and s ≤ 5/2, which are uniquely determined by the on-shell recursion relation and are free from unphysical spurious poles. In addition, we explore amplitudes of spin-3/2 particles with non-minimal three-point interactions with photon, as well as s > 3/2 particles, and comment on their notable features. Our work furthers the understanding of on-shell methods for massive amplitudes, with hopes to shed light on physical observables in particle physics and higher-spin amplitudes relevant for Kerr black-hole scattering.

We compute the tensor meson pole contributions to the Hadronic Light-by-Light piece of a_μ in the purely hadronic region, using Resonance Chiral Theory. Given the differences between the dispersive and holographic groups determinations and the resulting discussion of the corresponding uncertainty estimate for the Hadronic Light-by-Light section of the muon g − 2 theory initiative second White Paper, we consider timely to present an alternative evaluation. In our approach, in addition to the lightest tensor meson nonet, two vector meson resonance nonets are considered, in the chiral limit. Disregarding operators with derivatives, only the form factor ({mathcal{F}}_{1}^{T}) is non-vanishing, as assumed in the dispersive study. All parameters are determined by imposing a set of short-distance QCD constraints, and the radiative tensor decay widths. In this case, we obtain the following results for the different contributions (in units of 10⁻¹¹): ({a}_{mu }^{{text{a}}_{2}-{text{pole}}}=-left(1.02{left(10right)}_{text{stat}}{{(}_{-0.12}^{+0.00})}_{text{syst}}right)), ({a}_{mu }^{{text{f}}_{2}-{text{pole}}}=-left(3.2{left(3right)}_{text{stat}}{{(}_{-0.4}^{+0.0})}_{text{syst}}right)) and ({a}_{mu }^{{text{f}}_{2}{prime}-{text{pole}}}=-left(0.042{left(13right)}_{text{stat}}right)), which add up to ({a}_{mu }^{{text{a}}_{2}+{f}_{2}+{f}_{2}{prime}-{text{pole}}}=-left({4.3}_{-0.5}^{+0.3}right)), in close agreement with the holographic result when truncated to ({mathcal{F}}_{1}^{T}) only. However, with an ad-hoc extended Lagrangian, that also generates ({mathcal{F}}_{3}^{T}), as in the holographic approach, we have found: ({a}_{mu }^{{text{a}}_{2}-{text{pole}}}=+0.47{left(1.43right)}_{text{norm}}{left(3right)}_{text{stat}}{{(}_{-0.00}^{+0.06})}_{text{syst}}), ({a}_{mu }^{{text{f}}_{2}-{text{pole}}}=+1.18{left(4.18right)}_{text{norm}}{left(12right)}_{text{stat}}{{(}_{-0.00}^{+0.24})}_{text{syst}}) and ({a}_{mu }^{{text{f}}_{2}{prime}-{text{pole}}}=+0.040{left(78right)}_{text{norm}}{left(2right)}_{text{stat}}), summing to ({a}_{mu }^{{{a}_{2}+{f}_{2}+f}_{2}{prime}-{text{pole}}}=+1.7(4.4)), which agree with these recent determinations within uncertainties (dominated by the ({mathcal{F}}_{3}^{T}) normalization). We point out that RχT generates all five form factors, differently to previous approaches. The contributions to a_μ of ({mathcal{F}}_{text{2,4},5}) cannot be evaluated in the current basis, preventing for the moment a complete calculation of ({a}_{mu }^{text{T}-{text{pole}}{text{s}}}) within our framework.

We present the implementation of next-to-next-to-leading order (NNLO) QCD fully-differential corrections within the Geneva framework, for both colour-singlet and colour-singlet+jet processes at hadron colliders, by employing a nonlocal subtraction approach. In particular, we discuss the implementation details and the challenges that arise when utilizing a dynamical infrared cutoff parameter. Additionally, we combine the subtraction with the projection-to-Born method in order to include fiducial power corrections. As a test case, we provide predictions for Drell-Yan and Z+jet production at the LHC, using N-jettiness as resolution variable. We validate the NNLO corrections of Geneva against nnlojet finding excellent agreement. Finally, we discuss how to extend our method to calculate the N³LO QCD fully-differential corrections to colour-singlet production at hadron colliders.

In the phenomenological study of dark photon, its mass origin is usually not of concern. However, in theoretical model construction, its mass is often generated via a dark Higgs mechanism, which leads to the presence of a light (non-decoupled) dark Higgs particle. In this work, we study the impact of such a dark Higgs particle on the collider detection of the dark photon. We focus on the process of final state dark photon radiating dark Higgs, which is called dark final state radiation (FSR). Considering the effects on both the signal cross section and the distribution of the squared missing mass, the invisible dark photon search at BaBar is reanalyzed and a new exclusion limit for invisible dark photon is presented.