We compute the primary Lund plane density for jets initiated by a massive ($\textit{b}$) quark to single logarithmic accuracy in Quantum Chromodynamics (QCD). In order to capture mass effects, we consider quasi-collinear factorisation and we include contributions from the running of the QCD coupling and from collinear evolution, in a variable flavour-number scheme. Furthermore, the resummation of soft logarithms, including clustering effects, is performed numerically, keeping the full dependence on the $\textit{b}$-quark mass. While our all-order results can be applied to both hadron and lepton colliders, we present, as first phenomenological application, the resummed calculation of the Lund plane density in $\textit{e}$ $\textit{e}$ collisions at $$ \sqrt{s} $$ = $\textit{M}$ , matched to tree-level matrix elements.

Germany

Andrea Ghira

Italy

Simone Marzani

France

Gregory Soyez

The Lund $\textit{b}$-jet plane

<p>In bound systems whose constituent particles are heavier than the electron, the dominant radiative correction to energy levels is given by light-fermion (electronic) vacuum polarization. In consequence, relativistic and recoil corrections to the one-loop vacuum-polarization correction are phenomenologically relevant. Here, we generalize the treatment, previously accomplished for systems with orbiting muons, to bound systems of constituents with more general spins: spin-0, spin-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></math>, and spin-1. We discuss the application of our more general expressions to various systems of interest, including spinless systems (pionium), muonic hydrogen and deuterium, and devote special attention to the excited non-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math> states of deuteronium, the bound system of a deuteron and its antiparticle. The obtained energy corrections are of order <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>α</mi><mn>5</mn></msup><msub><mi>m</mi><mi>r</mi></msub></math>, where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>α</mi></math> is the fine-structure constant and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>r</mi></msub></math> is the reduced mass.</p>

United States

Gregory S. Adkins

Ulrich D. Jentschura

Relativistic and recoil corrections to light-fermion vacuum polarization for bound systems of spin-0, spin-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></math>, and spin-1 particles

We study two- and three-point correlation functions of chiral primary half-BPS operators in four-dimensional $$ \mathcal{N} $$ = 2 superconformal circular, cyclic symmetric quiver theories. Using supersymmetric localization, these functions can be expressed as matrix integrals which, in the planar limit, reduce to Fredholm determinants of certain semi-infinite matrices. This powerful representation allows us to investigate the correlation functions across the parameter space of the quiver theory, including both weak and strong coupling regimes and various limits of the number of nodes and the operator scaling dimensions. At strong coupling, the standard semiclassical AdS/CFT expansion diverges in the long quiver limit. However, by incorporating both perturbative corrections (in negative powers of the ’t Hooft coupling) and an infinite tower of nonperturbative, exponentially suppressed contributions, we derive a remarkably simple expression for the correlation functions in this limit. These functions exhibit exponential decay with increasing node separation and admit an interpretation within a five-dimensional effective theory. We determine the mass spectrum of excitations propagating along the emergent fifth dimension within this theory, finding it to be given by the zeros of Bessel functions.

Gregory Korchemsky

Alessandro Testa

Correlation functions in four-dimensional superconformal long circular quivers

We propose a new strategy to obtain a high-purity sample of gluon-initiated jets at the LHC. Our approach, inspired by the Lund jet plane picture, is to perform a dijet selection where the two jets are collinear to each other and their momentum fraction share is highly asymmetric, and to measure the primary Lund plane density of emissions of the subleading jet. The subleading jet in this topology is practically equivalent to a secondary Lund jet plane. We demonstrate by means of fixed-order calculations that such a simple setup yields (Born-level) gluon jet fractions of around 90% for the subleading jet for both quark- and gluon-initiated jets. This observation is confirmed using hadron-level Monte Carlo generated events. We also show that the extracted gluon purities are highly resilient to the overall colour structure of the event, to the flavour of the hard-scattering process, and to the parton distribution functions. This strategy is well-suited for constraining the radiation pattern of gluon-initiated jets using a set of fiducial cuts that can readily be tested at the LHC, without relying on taggers or statistical demixing.

Cristian Baldenegro

Spain

Alba Soto-Ontoso

Secondary Lund jet plane as a gluon-enriched sample

The wormhole solution in dRGT massive gravity is examined in this paper in the background of non-commutative geometry. In order to derive the wormhole model, along with the zero tidal force, we assume that the matter distribution is given by the Gaussian and Lorentzian distributions. The shape function in both models involves the massive gravity parameters <math><msup><mrow><mi>m</mi></mrow><mrow><mn>2</mn></mrow></msup><msub><mrow><mi>c</mi></mrow><mrow><mn>1</mn></mrow></msub></math> and <math><msup><mrow><mi>m</mi></mrow><mrow><mn>2</mn></mrow></msup><msub><mrow><mi>c</mi></mrow><mrow><mn>2</mn></mrow></msub></math>. But the spacetime loses its asymptotic flatness due to the action of the massive gravity parameter. It is noticed that the asymptotic flatness is affected by the repulsive effect induced in the massive gravitons that push the spacetime geometry very strongly. We observed that each model violates the null energy criteria, indicating the presence of exotic matter which is necessary to sustain the wormholes. The exotic matter is measured using the volume integral quantifier. Moreover, it is discovered that the model is stable under the hydrostatic equilibrium condition by utilizing the TOV equation. Finally, our research encompassed an exploration of the repulsive influence exerted by gravity. Our findings demonstrated that the presence of repulsive gravity results in a negative deflection angle for photons following null geodesics. Remarkably, we consistently observed negative values for the deflection angle across all values of <math><msub><mrow><mi>r</mi></mrow><mrow><mn>0</mn></mrow></msub></math> in the two scenarios examined. This consistent negativity unequivocally signifies the manifestation of the repulsive gravity effect.

India

China

South Africa

Noncommutative wormhole in de Rham-Gabadadze-Tolley like massive gravity

We reproduce and extend the previous studies of Lehner and Pretorius of the endpoint of the Gregory-Laflamme instability of black strings in five space-time dimensions. We consider unstable black strings of fixed thickness and different lengths, and in all cases we confirm that at the intermediate stages of the evolution the horizon can be interpreted as a quasistationary self-similar sequence of black strings connecting spherical black holes on different scales. However, we do not find any evidence for a global timescale relating subsequent generations. The endpoint of the instability is the pinch off of the horizon in finite asymptotic time, thus confirming the violation of the weak cosmic censorship conjecture around black string spacetimes.

United Kingdom

Endpoint of the Gregory-Laflamme instability of black strings revisited

We construct novel black strings that are neither time-translation invariant, nor axisymmetric, nor translationally invariant in the string direction, but nevertheless have a helical Killing vector field. These solutions branch from the superradiant instability of D = 6 Myers-Perry black strings with equal angular momenta. We coin these solutions as black resonator strings and we find that they have more entropy than Myers-Perry black strings for the energies and angular momenta where both solutions coexist. We also construct Kaluza-Klein geons, which share the symmetries of black resonator strings, but are horizonless. Unlike in other superradiant systems, Kaluza-Klein geons are not the horizonless limit of black resonator strings and are instead entirely separate solutions.

Japan

Gregory-Laflamme and superradiance encounter black resonator strings

We investigate the effect of superradiant scattering of gravitational perturbations on the stability of rotating black strings, focusing on the six dimensional equal-spinning Myers-Perry black string. We find that rapidly rotating black strings are unstable to gravitational superradiant modes within a bounded range of string lengths. The instability occurs because momentum along the string direction creates a potential barrier that allows for the confinement of superradiant modes. Yet, five dimensional Myers-Perry black holes do not have stable particle orbits so, unlike other known superradiant systems, these black strings remain stable to perturbations with sufficiently high azimuthal mode number — this is a ‘finite-m’ superradiant instability. For some parameters, this instability competes with the Gregory-Laflamme instability, but otherwise exists independently. The onset of this instability is degenerate and branches to multiple steady-state solutions. This paper is the first of a trilogy: in the next two, we construct two distinct families of rotating strings emerging from the superradiant onset (the ‘black resonator strings’ and ‘helical black strings’). We argue that similar physics is present in 5-dimensional Kerr black strings, but not in D &gt; 6 equal-spinning Myers-Perry black strings.

Gregory-Laflamme encounters Superradiance

In this work, we study the thin-shell wormholes in dRGT massive gravity. In order to glue two bulks of the spacetime geometry, we first derive junction conditions of the dRGT spacetime. We obtain the dynamics of the spherical thin-shell wormholes in the dRGT theory. We show that the massive graviton correction term of the dRGT theory in the Einstein equation is represented in terms of the effective anisotropic pressure fluid. However, if there is only this correction term, without invoking exotic fluids, we find that the thin-shell wormholes cannot be stabilized. We then examine the stability conditions of the wormholes by introducing four existing models of the exotic fluids at the throat. In addition, we analyze the energy conditions for the thin-shell wormholes in the dRGT massive gravity by checking the null, weak, and strong conditions at the wormhole throat. We show that in general the classical energy conditions are violated by introducing all existing models of the exotic fluids. Moreover, we quantify the wormhole geometry by using the embedding diagrams to represent a thin-shell wormhole in the dRGT massive gravity.

Thailand

Thin-shell wormholes in de Rham–Gabadadze–Tolley massive gravity

The effect of massive scalar perturbations on neutral black string in de Rham–Gabadadze–Tolley (dRGT) massive gravity is investigated through the study of the quasi-normal modes (QNMs). Due to the similarity between the equation of motion of the field in the black-string and black-hole background, similar numerical and analytical techniques can be used to explore the behaviour of the QNMs. We use the asymptotic iteration method (AIM) and the WKB method to numerically calculate the QNMs of scalar perturbation in the black string background with positive cosmological constant. High-momentum behaviour of such QNMs can be analytically approximated by the first-order WKB method with excellent accuracy. For near-extremal black string with event horizon very close to the cosmological horizon, the Pöschl–Teller technique gives accurate analytic formula for the QNMs. When massive-gravity-parameter $$\gamma $$ <math><mi>γ</mi></math>  increases, we found that the scalar modes oscillate with higher frequencies and decay faster. The QNMs of black string in spacetime with negative cosmological constant are explored in all range of possible $$\gamma $$ <math><mi>γ</mi></math>  using the spectral method. We found the movement of the holographic sound poles to collide and form diffusive poles as $$\gamma $$ <math><mi>γ</mi></math>  changes from positive to negative values. We observe no evidence of instability of neutral black string in both positive and negative cosmological constant cases.