In this paper, we present topological defects in (1, 1) dimensions, described by an extended nonlinear $\textit{O}$(3) sigma model. We consider spherical coordinates ($\textit{ϕ}$, $\textit{χ}$) in the isotopic space $\textit{S}$ and a potential $\textit{V}$ ($\textit{ϕ}$, $\textit{χ}$). For specific forms of the potential, the Bogomolnyi method is applicable, yielding first-order equations of motion with solutions that minimize energy. We study a model with an explicit solution for the field $\textit{ϕ}$ that resembles the ubiquitous sine-Gordon kink/antikink but with an internal structure given by the field $\textit{χ}$ with a form antilump/lump that depends on a constant $\textit{C}$. The soliton-antisoliton scattering process depends on $\textit{C}$ and on the initial velocity of the pair. Some results are reported, such as: one-bounce scattering for $\textit{ϕ}$, or strong radiation emission for $\textit{ϕ}$, followed by i) annihilation of $\textit{χ}$; ii) same pattern antilump-antilump or lump-antilump for $\textit{χ}$; iii) inversion antilump-antilump to lump-lump for $\textit{χ}$; iv) inversion antilump-lump to lump-antilump for $\textit{χ}$. Other findings are: v) annihilation of the soliton-antisoliton pair with the emission of scalar radiation; vi) emission of a pair of oscillating pulses around the vacuum. The energy density indicates that the defect possesses an internal structure, specifically as a nested defect of an antilump within a kink. The lump core of the defect is responsible for emitting radiation. The change in the structure of the defects during scattering is analyzed not only in terms of field profiles in the physical (1, 1) space but also in the internal $\textit{S}$ space, which provides new insight into the process.

Brazil

Adalto Gomes

Fabiano Simas

Scattering of sine-Gordon kinks with internal structure in an extended nonlinear $\textit{O}$(3) sigma model

The black hole information paradox has been an important problem in quantum gravity. In the study of evaporating black hole, it has been proposed that the holographic map between the semiclassical effective description in bulk and the fundamental description in boundary cannot be isometric. In this work, we would like to study the reflected entropy in an evaporating black hole model through a nonisometric holographic map. We assume that the evaporating is slow enough that it makes sense to ascribe a slowly varying temperature to the Hawking radiation. We then introduce a two-sided black hole model to canonically purify the semiclassical state. The holographic map to the fundamental description is nonisometric and defined by a Haar random unitary matrix. We show that the entropy of radiation in the model computed in the fundamental description matches the result read from the quantum extremal surface formula and agrees with the Page curve. Furthermore, through a nonisometric holographic map, we study the reflected entropies between different regions, including the one between the black holes on different sides, the one between the radiations distributed symmetrically but disconnectedly, and the one between the black hole and the radiation on a single side. Our results are consistent with the existing ones based on the effective descriptions.

China

Bin Chen

Zhi-jun Yin

Reflected entropy in an evaporating black hole through a nonisometric map

We consider fermionic and scalar dark matter (DM) candidates that couple predominantly to third-generation Standard Model fermions, describing their interactions within an effective field theory framework. We show that current direct-detection constraints on these interactions are more than an order of magnitude weaker than those for flavor-universal couplings: effective scales in the few-TeV range remain allowed by existing data, leaving open the possibility of a connection between this type of new physics and a solution to the electroweak hierarchy problem. Imposing the observed relic abundance from thermal freeze-out within the same effective theory, a well-defined region for a fermionic DM candidate with mass in the 1–2 TeV range emerges. Notably, this region will be fully probed by upcoming direct-detection experiments. Finally, we show that additional parameter space for both fermion and scalar cases can be recovered by going beyond the effective theory, through the introduction of a suitable vector mediator enabling resonant DM annihilation.

Switzerland

Georgios Demetriou

Gino Isidori

Gioacchino Piazza

Emanuelle Pinsard

The third-generation-philic WIMP: an EFT analysis

We report the first measurement of neutron capture multiplicity in neutrino-oxygen neutral-current quasielasticlike interactions at the gadolinium-loaded Super-Kamiokande detector using the T2K neutrino beam, which has a peak energy of about 0.6 GeV. A total of 30 neutral-current quasielasticlike event candidates were selected from T2K data corresponding to an exposure of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1.76</mn><mo>×</mo><msup><mn>10</mn><mn>20</mn></msup></math> protons on target. The <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi></math> ray signals resulting from neutron captures were identified using a neural network. The flux-averaged mean neutron capture multiplicity was measured to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mn>1.37</mn><mo>±</mo><mn>0.33</mn><mtext> </mtext><mo stretchy="false">(</mo><mi>stat</mi><mo>.</mo><mo stretchy="false">)</mo></mrow><mrow><mo>−</mo><mn>0.27</mn></mrow><mrow><mo>+</mo><mn>0.17</mn></mrow></msubsup><mtext> </mtext><mo stretchy="false">(</mo><mi>syst</mi><mo>.</mo><mo stretchy="false">)</mo></mrow></math>, which is compatible within 2.3 sigma than predictions obtained using our nominal simulation. We discuss potential sources of systematic uncertainty in the prediction and demonstrate that a significant portion of this discrepancy arises from the modeling of hadron-nucleus interactions in the detector medium.

Japan

K. Abe

S. Abe

R. Akutsu

United Kingdom

H. Alarakia-Charles

Y.I. Alj Hakim

S. Alonso Monsalve

L. Anthony

S. Aoki

K.A. Apte

T. Arai

T. Arihara

S. Arimoto

Y. Ashida

E.T. Atkin

United States

N. Babu

JINR

V. Baranov

G.J. Barker

G. Barr

D. Barrow

P. Bates

L. Bathe-Peters

Poland

M. Batkiewicz-Kwasniak

N. Baudis

Italy

V. Berardi

L. Berns

S. Bhattacharjee

CERN

A. Blanchet

France

A. Blondel

P.M.M. Boistier

S. Bolognesi

S. Bordoni

S.B. Boyd

C. Bronner

A. Bubak

M. Buizza Avanzini

Spain

J.A. Caballero

F. Cadoux

N.F. Calabria

Vietnam

S. Cao

S. Cap

D. Carabadjac

S.L. Cartwright

M.P. Casado

M.G. Catanesi

J. Chakrani

A. Chalumeau

D. Cherdack

Russia

A. Chvirova

J. Coleman

G. Collazuol

Canada

F. Cormier

A.A.L. Craplet

A. Cudd

D. D’ago

C. Dalmazzone

T. Daret

Hungary

P. Dasgupta

C. Davis

Yu. I. Davydov

P. de Perio

G. De Rosa

T. Dealtry

C. Densham

A. Dergacheva

R. Dharmapal Banerjee

F. Di Lodovico

G. Diaz Lopez

S. Dolan

D. Douqa

T.A. Doyle

O. Drapier

K.E. Duffy

J. Dumarchez

P. Dunne

K. Dygnarowicz

A. Eguchi

J. Elias

S. Emery-Schrenk

G. Erofeev

A. Ershova

G. Eurin

D. Fedorova

S. Fedotov

M. Feltre

L. Feng

D. Ferlewicz

A.J. Finch

M.D. Fitton

C. Forza

M. Friend

Y. Fujii

Y. Fukuda

Y. Furui

Belgium

J. García-Marcos

A.C. Germer

L. Giannessi

C. Giganti

M. Girgus

V. Glagolev

M. Gonin

First measurement of neutron capture multiplicity in neutrino-oxygen neutral-current quasielasticlike interactions using an accelerator neutrino beam

Various candidate theories of quantum gravity suggest the existence of a minimum measurable length at the Planck scale, which leads to the generalization of the Heisenberg Uncertainty Principle (HUP) to the Generalized Uncertainty Principle (GUP). This generalization could potentially result in observable effects even below the Planck energy scale, offering an opportunity to investigate quantum gravity theories through physical processes at lower energy scale. In this paper, we study, within the framework of the DDC formalism, the effect of GUP on the spontaneous excitation and de-excitation of a multilevel atom in both inertial and non-inertial motions coupled to a vacuum electromagnetic field. The GUP modifies the two point function of the electromagnetic field, thereby affecting the radiative properties of atom. We show that the GUP can alter the rate of change of mean atomic energy, resulting in either an enhancement or a reduction, depending on the sign of the GUP parameter <italic>&#946;</italic>. Furthermore, the corrections induced by the GUP for an atom in uniformly accelerated motion, containing components proportional to <math altimg='si1.svg'><msup><mrow><mi>a</mi></mrow><mrow><mn>4</mn></mrow></msup></math>, suggest that the GUP effect may be amplified by significant acceleration of the atom, thus providing a potential avenue for experimental testing.

Zhi Wang

Zhengwen Long

GUP corrections to the spontaneous excitation of an accelerated atom coupled with electromagnetic vacuum fluctuations

We classify radiative corrections to spin polarization into three types: (i) spectral function, (ii) modified distribution function, and (iii) modified Kubo-Martin-Schwinger relation. The last two contributions modify the well-known free theory results. The first contribution is present with radiative correction only. We perform a detailed analysis on the first type for an energetic quark in a medium with hydrodynamic gradients, finding the radiative correction to spectral function leads to a polarized quasiparticle. The degeneracy of spin polarization induced by different hydrodynamic sources in free theory is lifted by radiative correction. We argue that the corrections of the last two types are parametrically suppressed with respect to the first type for the energetic quark we consider.

Shu Lin

Jiayuan Tian

Spin polarized quasiparticle in an off-equilibrium medium

In a canonical type-I seesaw scenario, the Standard Model is extended with three singlet right-handed neutrinos (RHNs) <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mi>i</mi></msub><mo>,</mo><mi>i</mi><mo>=</mo><mn>1</mn></math>, 2, 3 with masses <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>M</mi><mi>i</mi></msub><mo>,</mo><mi>i</mi><mo>=</mo><mn>1</mn></math>, 2, 3 to simultaneously explain sub-eV masses of light neutrinos and baryon asymmetry of the Universe at high scales. In this paper, we show that a relatively low-scale thermal leptogenesis accompanied by gravitational wave signatures is possible when the type-I seesaw is extended with a singlet fermion (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math>) and a singlet scalar (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ρ</mi></math>), where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ρ</mi></math> are odd under a discrete <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mn>2</mn></msub></math> symmetry. We also add a vectorlike fermion doublet <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Ψ</mi></math> and impose a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>Z</mi><mn>2</mn><mo>′</mo></msubsup></math> symmetry under which both <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mn>1</mn></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Ψ</mi></math> are odd while all other particles are even. This gives rise to a singlet-doublet Majorana fermion dark matter in our setup. At a high scale, the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mn>2</mn></msub></math> symmetry is broken spontaneously by the vacuum expectation value of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ρ</mi></math> and leads to (i) mixing between RHNs (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>N</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>N</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow></math>) and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math> and (ii) formation of Domain walls (DWs). In the former case, the final lepton asymmetry is generated by the out-of-equilibrium decay of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math>, which dominantly mixes with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mn>2</mn></msub></math>. We show that the scale of thermal leptogenesis can be lowered to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>M</mi><mi>S</mi></msub><mo>∼</mo><mn>2</mn><mo>×</mo><msup><mn>10</mn><mn>6</mn></msup><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>, which is 3 orders of magnitude lower than the thermal leptogenesis in canonical type-I seesaw. In the latter case, the disappearance of the DWs gives observable gravitational wave signatures, which can be probed at LISA, DECIGO, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>μ</mi><mrow><mi>ARES</mi></mrow></math> etc.

India

Partha Kumar Paul

Narendra Sahu

Prashant Shukla

Thermal leptogenesis, dark matter, and gravitational waves from an extended canonical seesaw scenario

We explore <math altimg='si1.svg'><mn>2</mn><mo linebreak='goodbreak' linebreakstyle='after'>+</mo><mn>1</mn></math>-dimensional scalar-tensor theories derived from well-defined dimensional regularizations of the Lovelock invariants. In the limit where an infinite series of corrections is included, we obtain theories that admit fully regular black hole solutions. We analyze the properties of these regular black holes, investigate geodesics in these spacetimes, and examine the tidal forces, finding they remain finite everywhere.

Germany

Pedro G.S. Fernandes

Regular BTZ black holes from an infinite tower of corrections

At nonzero temperatures, the deconfining phase transition can be analyzed using an effective matrix model to characterize the change in holonomy. The model includes gluons and two-dimensional ghost fields in the adjoint representation, or “teens.” As ghosts, the teen fields are responsible for the decrease of the pressure as <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi><mo stretchy="false">→</mo><msub><mi>T</mi><mi>d</mi></msub></math>, with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mi>d</mi></msub></math> the transition temperature for deconfinement. Using the solution of this matrix model for a large number of colors, the parameters of the teen fields are adjusted so that the expectation value of the Polyakov loop is close to the values from the lattice. The shear, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>η</mi></math>, and bulk, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ζ</mi></math>, viscosities are computed at nonzero holonomy to leading logarithmic order in weak coupling. In the pure glue theory, the value of the Polyakov loop is relatively large in the deconfined phase, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>≈</mo><mn>1</mn><mo>/</mo><mn>2</mn></math> at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mi>d</mi></msub></math>. Consequently, if <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>s</mi></math> is the entropy density, while <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>η</mi><mo>/</mo><mi>s</mi></math> decreases as <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi><mo stretchy="false">→</mo><msub><mi>T</mi><mi>d</mi></msub></math>, it is still well above the conformal bound. In contrast, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ζ</mi><mo>/</mo><mi>s</mi></math> is largest at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mi>d</mi></msub></math>, comparable to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>η</mi><mo>/</mo><mi>s</mi></math>, then falls off rapidly with increasing temperature and is negligible by <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>∼</mo><mn>2</mn><msub><mi>T</mi><mi>d</mi></msub></math>.

Manas Debnath

Ritesh Ghosh

Najmul Haque

Yoshimasa Hidaka

Robert D. Pisarski

Shear and bulk viscosity for a pure glue theory using an effective matrix model

In this paper, we analyze the potential variation of the gravitational constant <italic>G</italic> using data from strong gravitational lensing systems and Type Ia supernovae. Testing <math altimg='si1.svg'><mi>G</mi><mo stretchy='false'>(</mo><mi>z</mi><mo stretchy='false'>)</mo></math> parameterizations where <math altimg='si2.svg'><mi>G</mi><mo stretchy='false'>(</mo><mi>z</mi><mo stretchy='false'>)</mo><mo linebreak='goodbreak' linebreakstyle='after'>=</mo><msub><mrow><mi>G</mi></mrow><mrow><mn>0</mn></mrow></msub><mo stretchy='false'>(</mo><mn>1</mn><mo linebreak='badbreak' linebreakstyle='after'>+</mo><msub><mrow><mi>G</mi></mrow><mrow><mn>1</mn></mrow></msub><mi>z</mi><mo stretchy='false'>)</mo></math> and <math altimg='si3.svg'><mi>G</mi><mo stretchy='false'>(</mo><mi>z</mi><mo stretchy='false'>)</mo><mo linebreak='goodbreak' linebreakstyle='after'>=</mo><msub><mrow><mi>G</mi></mrow><mrow><mn>0</mn></mrow></msub><msup><mrow><mo stretchy='false'>(</mo><mn>1</mn><mo linebreak='badbreak' linebreakstyle='after'>+</mo><mi>z</mi><mo stretchy='false'>)</mo></mrow><mrow><msub><mrow><mi>G</mi></mrow><mrow><mn>1</mn></mrow></msub></mrow></msup></math>, we also account for the influence of <italic>G</italic> on the luminosity of SNe Ia through the Chandrasekhar mass-luminosity relation. Only the flat universe hypothesis is considered. Constraints from 158 lensing systems and the Pantheon+ sample show no significant evidence of <italic>G</italic> variation. However, although the results are compatible with no variation, the errors are not yet sufficiently restrictive to rule out any variation of <italic>G</italic> with high statistical confidence. This study highlights the viability of using combined astrophysical data to probe variations in fundamental constants, suggesting that future surveys could refine these constraints.

R.F.L. Holanda

Marcelo Ferreira

Javier E. Gonzalez

An investigation of a varying G through Strong Lensing and SNe Ia observations