In this study, we investigate the possibility of enhancing the di-jet resonance searches by tagging the final state radiation (FSR) jet using an event-level deep neural network. It is found that solely relying on the 4-momenta of the leading three jets allows the algorithm to achieve good discriminating power that can identify the hardest FSR jet in the signal while rejecting other soft jets. Once the invariant mass is corrected with the tagged FSR jet, the mass resolution of the signal is greatly enhanced, and the sensitivity of the search is also improved by more than 10%. By crafting the input variables carefully, the algorithm introduces minimal mass sculpting for the background, and its applicability extends to a broad mass range. This work proves that FSR jet tagging can potentially enhance di-jet resonance searches, suiting various stages of the physics programmes at the Large Hadron Collider (LHC) and High-Luminosity LHC (HL-LHC).

China

Bingxuan Liu

Yuxuan Shen

Yuanshunzi Sui

Enhancing di-jet resonance searches via a final-state radiation jet tagging algorithm * Bingxuan Liu is supported by Shenzhen Campus of the Sun Yat-sen University under project 74140-12255011, and by the Young Scientists Fund (C Class) of the National Natural Science Foundation of China (12405122). Both Yuxuan Shen and Yuanshunzi Sui are supported by College Students’ Innovative Entrepreneurial Training Plan Program

We investigated the effect of an isospin chemical potential ( $ \mu_{I} $ ) within the quark-meson model, which approximates quantum chromodynamics (QCD) by modeling low-energy phenomena such as chiral symmetry breaking and phase structure under varying conditions of temperature and chemical potential. Using the functional renormalization group (FRG) flow equations, we calculated the phase diagram in the chiral limit within the two-flavor quark-meson model in a finite $ \mu_{I} $ with $\textit{ρ}$ vector meson interactions. Fluctuation effects significantly decrease the critical chemical potential from the mean-field (MF) value $\mu_{I,{\rm MF}} \gt m_\rho$ to a lower value at which the $\textit{ρ}$ vector meson condensates alongside the chiral condensate once the isospin chemical potential exceeds the critical value $ \mu_{I}^{{\rm{crit}}} $ . This $\textit{ρ}$ condensation was investigated numerically for different meson coupling strengths. The $\textit{ρ}$ meson dominated region is delineated from other phases by a second-order phase transition at lower $ \mu_{I} $ and a first-order transition at slightly higher $ \mu_{I} $ .

Mohammed Osman

Defu Hou

Wentao Wang

United States

Hui Zhang

Functional renormalization group study of $\textit{ρ}$ meson condensate at a finite isospin chemical potential in the quark meson model * Supported in part by the National Key Research and Development Program of China (2022YFA1604900). This work is also partly supported by the National Natural Science Foundation of China (NSFC) (12435009, 12275104). Hui Zhang acknowledges the financial support from the Guangdong Major Project of Basic and Applied Basic Research (2020B0301030008) and the National Natural Science Foundation of China (12047523, 12105107)

A new model based on the relativistic Boltzmann equation in the isotropization time approximation is developed to investigate the collective behavior of the quark-gluon plasma produced in high-energy heavy-ion collisions. The equation is solved in <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>(</mo><mn>2</mn><mo>+</mo><mn>2</mn><mo>)</mo><mi mathvariant="normal">D</mi></mrow></math> (two spatial and two momentum-space dimensions). This framework couples preequilibrium dynamics with hydrodynamic evolution to simulate the dynamics of quasiparticle evolution. A numerical scheme based on the method of characteristics enables the evolution to begin from a specified initial Boltzmann distribution. In this work, the spatial structure of the initial distribution is modeled using the Trento framework. Our results show that a medium initialized at <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>τ</mi><mn>0</mn></msub></math> on the order of <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mn>1</mn><mspace width="0.16em"></mspace><mi>fm</mi><mo>/</mo><mi>c</mi></mrow></math> with a small shear viscosity to entropy density ratio (<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>η</mi><mo>/</mo><mi>s</mi><mo>=</mo><mn>0.008</mn></mrow></math>) evolves consistently with hydrodynamic simulations, such as those performed using the vish2+1 code, while discrepancies arise for a medium with <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>η</mi><mo>/</mo><mi>s</mi><mo>=</mo><mn>0.8</mn></mrow></math>. Furthermore, when initialized with a highly anisotropic momentum distribution in the longitudinal direction at early times, the system exhibits spatially nonuniform thermalization in the transverse plane, leading to the emergence of a nontrivial hypersurface that marks the onset of hydrodynamic applicability. Finally, we compute the <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>p</mi><mi>T</mi></msub></math>-spectra for a nonfluctuating initial condition using the hybrid version of CoMBolt-ITA. In this hybrid setup, the description is switched from quasiparticles to hadrons, and UrQMD is used to model the hadron gas dynamics. We compare these results with those obtained from the hybrid vish2+1 initialized within the same setup. For a small shear viscosity, <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>η</mi><mo>/</mo><mi>s</mi><mo>=</mo><mn>0.08</mn></mrow></math>, the two results show a good level of consistency, whereas for a larger value, <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>η</mi><mo>/</mo><mi>s</mi><mo>=</mo><mn>0.8</mn></mrow></math>, a noticeable discrepancy emerges.

Germany

S.F. Taghavi

Iran

S.M.A. Tabatabaee Mehr

F. Taghinavaz

<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>(</mo><mn>2</mn><mo>+</mo><mn>2</mn><mo>)</mo><mi mathvariant="normal">D</mi></mrow></math> collective model based on a relativistic Boltzmann equation in the isotropization-time approximation: CoMBolt-ITA

Results are presented on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>χ</mi></mrow><mrow><mi>b</mi><mn>1</mn><mo>,</mo><mn>2</mn></mrow></msub><mo stretchy="false">(</mo><mn>2</mn><mi>P</mi><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>ω</mi><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>1</mn><mi>S</mi><mo stretchy="false">)</mo></mrow></math> transitions from <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mrow><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow><mo stretchy="false">→</mo><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>3</mn><mi>S</mi><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>γ</mi><msub><mrow><mi>χ</mi></mrow><mrow><mi>b</mi><mn>1</mn><mo>,</mo><mn>2</mn></mrow></msub><mo stretchy="false">(</mo><mn>2</mn><mi>P</mi><mo stretchy="false">)</mo></mrow></math> decays. The data were collected with the BABAR detector at the PEP-II asymmetric-energy <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup></math> collider at SLAC. The integrated luminosity of the data sample is <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>28.0</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>, corresponding to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>121.3</mn><mo>×</mo><msup><mn>10</mn><mn>6</mn></msup></math> <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>3</mn><mi>S</mi><mo stretchy="false">)</mo></math> decays. Signals of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>b</mi><mn>1</mn><mo>,</mo><mn>2</mn></mrow></msub><mo stretchy="false">(</mo><mn>2</mn><mi>P</mi><mo stretchy="false">)</mo></math> are observed over a negligible background. Improved precision measurements of branching fractions are obtained. First measurements of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>b</mi><mn>1</mn><mo>,</mo><mn>2</mn></mrow></msub><mo stretchy="false">(</mo><mn>2</mn><mi>P</mi><mo stretchy="false">)</mo></math> angular distributions are performed. No evidence is found for the presence of a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mi>χ</mi><mrow><mi>b</mi><mn>0</mn></mrow></msub><mo stretchy="false">(</mo><mn>2</mn><mi>P</mi><mo stretchy="false">)</mo></mrow><mo stretchy="false">→</mo><mi>ω</mi><mrow><mi mathvariant="normal">ϒ</mi><mrow><mo stretchy="false">(</mo><mn>1</mn><mi>S</mi><mo stretchy="false">)</mo></mrow></mrow></math> decay mode.

J.P. Lees

V. Poireau

V. Tisserand

E. Grauges

A. Palano

G. Eigen

D.N. Brown

Yu. G. Kolomensky

M. Fritsch

H. Koch

R. Cheaib

C. Hearty

T.S. Mattison

J.A. McKenna

R.Y. So

V.E. Blinov

A.R. Buzykaev

V.P. Druzhinin

E.A. Kozyrev

E.A. Kravchenko

S.I. Serednyakov

Yu. I. Skovpen

E.P. Solodov

K. Yu. Todyshev

A.J. Lankford

B. Dey

J.W. Gary

O. Long

A.M. Eisner

W.S. Lockman

W. Panduro Vazquez

D.S. Chao

C.H. Cheng

B. Echenard

K.T. Flood

D.G. Hitlin

Y. Li

D.X. Lin

S. Middleton

T.S. Miyashita

P. Ongmongkolkul

J. Oyang

F.C. Porter

M. Röhrken

B.T. Meadows

M.D. Sokoloff

J.G. Smith

S.R. Wagner

D. Bernard

M. Verderi

D. Bettoni

C. Bozzi

R. Calabrese

G. Cibinetto

E. Fioravanti

I. Garzia

E. Luppi

V. Santoro

A. Calcaterra

R. de Sangro

G. Finocchiaro

S. Martellotti

P. Patteri

I.M. Peruzzi

M. Piccolo

M. Rotondo

A. Zallo

S. Passaggio

C. Patrignani

B.J. Shuve

H.M. Lacker

B. Bhuyan

U. Mallik

C. Chen

J. Cochran

S. Prell

A.V. Gritsan

N. Arnaud

M. Davier

F. Le Diberder

A.M. Lutz

G. Wormser

D.J. Lange

D.M. Wright

J.P. Coleman

D.E. Hutchcroft

D.J. Payne

C. Touramanis

A.J. Bevan

M. Bona

F. Di Lodovico

G. Cowan

Sw. Banerjee

C.L. Davis

A.G. Denig

W. Gradl

K. Griessinger

A. Hafner

K.R. Schubert

Study of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>χ</mi></mrow><mrow><mi>b</mi><mn>1</mn><mo>,</mo><mn>2</mn></mrow></msub><mo stretchy="false">(</mo><mn>2</mn><mi>P</mi><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>ω</mi><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>1</mn><mi>S</mi><mo stretchy="false">)</mo></mrow></math> transitions in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>3</mn><mi>S</mi><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>γ</mi><msub><mrow><mi>χ</mi></mrow><mrow><mi>b</mi><mn>1</mn><mo>,</mo><mn>2</mn></mrow></msub><mo stretchy="false">(</mo><mn>2</mn><mi>P</mi><mo stretchy="false">)</mo></mrow></math> decays at BABAR

The strong coupling regime of four-dimensional <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>N</mi><mo>=</mo><mn>2</mn></math> supersymmetric vacua of the heterotic string is analyzed from a dual domain wall perspective. Using modular invariance, we compute a closed form for the nonperturbative corrections to the supersymmetric domain wall equations, which enables a quantitative study of gravitational strong coupling regimes. A strong coupling singularity for the hidden Hořava-Witten 9-brane is resolved, and the domain wall interpolates between the visible 9-brane and a supersymmetric anti–de Sitter vacuum, thereby realizing a variant of the Randall-Sundrum model.

Slovenia

Mirjam Cvetič

Max Wiesner

Smooth String Vacua in a Gravitationally Nonperturbative Regime

We revisit the renormalization of the gauge coupling in massless QED coupled to a scaleless quadratic theory of gravity. We compare two alternative prescriptions for the running of the electric charge: (i) the conventional <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>μ</mi></math> running in minimal subtraction, and (ii) a physical running extracted from the logarithmic dependence of amplitudes on a hard scale <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>Q</mi><mn>2</mn></msup></math> (e.g., <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>p</mi><mn>2</mn></msup></math> or a Mandelstam invariant) after removing IR effects. At one loop, using dimensional regularization with an IR mass regulator <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>m</mi></math>, we compute the photon vacuum polarization. We find a clean separation between UV and soft logarithms: the former is gauge and process independent and fixes the beta function, whereas the latter encodes nonlocal, IR-dominated contributions that may depend on gauge parameters and must not be interpreted as UV running. In the quadratic-gravity sector, the photon self-energy is UV finite—the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>ln</mi><msup><mrow><mi>μ</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></math> pieces cancel—leaving only <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ln</mi><mo stretchy="false">(</mo><msup><mi>Q</mi><mn>2</mn></msup><mo>/</mo><msup><mi>m</mi><mn>2</mn></msup><mo stretchy="false">)</mo></math> soft (IR) logs, which do not contribute to the running of the coupling once IR effects are consistently removed. Consequently, quadratic gravity does not modify the one-loop UV coefficient and thus does not alter <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>β</mi><mo stretchy="false">(</mo><mi>e</mi><mo stretchy="false">)</mo></math>. Therefore, the physical running coincides with the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>μ</mi></math> running in QED at one loop. Our analysis clarifies how to extract a gauge and process independent running in the presence of gravitational interactions and why soft logs from quadratic gravity should not contribute to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>β</mi><mo stretchy="false">(</mo><mi>e</mi><mo stretchy="false">)</mo></math>.

Brazil

M. Gomes

A.C. Lehum

A.J. da Silva

Physical running of the electric charge in a dimensionless theory of gravity

The scale of the seesaw mechanism is typically much larger than the electroweak scale. This hierarchy can be naturally explained by U(1) symmetry, which after spontaneous symmetry breaking, simultaneously generates Majorana masses for neutrinos and produces a network of cosmic strings. Such strings generate a gravitational wave (GW) spectrum which is expected to be almost uniform in frequency unless there is a departure from the usual early radiation domination. We explore this possibility in Type I, II and III seesaw frameworks, finding that only for Type-I, long-lived right-handed neutrinos (RHN) may provide a period of early matter domination for parts of the parameter space, even if they are thermally produced. Such a period leaves distinctive imprints in the GW spectrum in the form of characteristic breaks and a knee feature, arising due to the end and start of the periods of RHN domination. These features, if detected, directly determine the right-handed neutrino mass $\textit{M}$, and associated left-handed effective neutrino mass $$ \overset{\sim }{m} $$ of the dominating RHN. We find that GW detectors like LISA and ET could probe RHN masses in the range $\textit{M}$ ∈ [0.1, 10 ] GeV and effective neutrino masses in the $$ \overset{\sim }{m} $$ ∈ [10 , 10 ] eV range. We investigate the phenomenological implications of long-lived right-handed neutrinos for both local and global U(1) strings, focusing on dark matter production and leptogenesis. We map the viable and detectable parameter space for successful baryogenesis and asymmetric dark matter production from right-handed neutrino decays. We derive analytical and semi-analytical relations correlating the characteristic gravitational-wave frequencies to the neutrino parameters $$ \overset{\sim }{m} $$ and $\textit{M}$, as well as to the relic abundances of dark matter and baryons. We find that the detectable parameter space reaches the boundary of hierarchical leptogenesis and encompasses a substantial portion of the near-resonant regime.

Satyabrata Datta

Poland

United Kingdom

Anish Ghoshal

Angus Spalding

Graham White

Gravitational wave spectral shapes as a probe of long lived right-handed neutrinos, leptogenesis and dark matter. Global versus local $\textit{B}$ − $\textit{L}$ cosmic strings

Cosmogenic muon-induced radioactive isotopes pose a significant background source for deep-underground low-background experiments. Although rock overburdens at underground sites substantially attenuate the cosmogenic muon flux, residual muon-induced backgrounds still require active suppression. For future multi-kiloton liquid scintillator (LS) detectors, such as the Jiangmen Underground Neutrino Observatory (JUNO), shower muons contribute to more than 88% of all muon-induced isotopes. Consequently, precise reconstruction of shower vertices is essential for implementing localized spatial vetoes. We propose a novel waveform-based method to reconstruct the shower vertex, defined as the energy-deposition centroid in radius of 2 m. By subtracting the track contributions from non-shower muons in the recorded waveforms, the isolated shower component is extracted. Subsequently, using a photon propagation model and an iterative optimization algorithm, the shower vertex positions are reconstructed. Simulations show that for 68% of events, the single shower vertex resolution is better than 0.16 m, 0.15 m, and 0.26 m along X, Y, and Z respectively. Furthermore, the reconstruction efficiency exceeds 96% when requiring the distance between the reconstructed and true vertices to be less than 3.0 m. This method provides a critical technical foundation for muon-induced background suppression in JUNO and other large-scale LS detectors.

Junwei Zhang

Yongpeng Zhang

Yongbo Huang

Jilei Xu

Junyou Chen

Yi Wang

Reconstruction of the effective energy-deposition vertex of muon showers using PMT waveform in a large-scale liquid scintillator detector

Recently it has been shown that certain aspects of changing states in holography can be studied by considering the Berry Phase properties of simple entangled qubit systems. In this context the term wormhole quantum mechanics has been coined. In particular an interesting interplay between entanglement and Berry Phase was found. Here we present a mixed state generalization of this connection illustrated for a simple parametrized family of entangled quantum systems in the thermofield double state.

Hungary

Péter Lévay

Csaba Velich

A thermofield-double model of Uhlmann’s anholonomy

The double copy relates scattering amplitudes and classical solutions in non-abelian gauge theories and gravity. As such, it is usually expressed in the conventional second-order formalisms in both theories corresponding to standard Yang-Mills theory, and the Einstein-Hilbert action in General Relativity. In this paper, we instead consider alternative formulations of gravity, which are known to terminate at finite order in the coupling at Lagrangian level. We focus in particular on the Chern-Simons-Witten (CSW) formulation in 2+1 dimensions, and argue that the double copy then becomes a doppelgänger relationship between gauge theory and gravity, allowing straightforward replacement of generators and structure constants in both theories. We show how explicit (multiple) static point-source solutions can be mapped in the two approaches, and use the CSW formalism to examine when double copies are expected to be possible, and when not. In addition, we present an explicit double copy between the Wong equations for colour charges, and the Mathisson-Papapetrou-Dixon equations for spinning particles, that extends also to higher dimensions.

Nathan Moynihan

Michael Reichenberg Ashby

Chris White

The double copy as a doppelgänger