A search for leptons displaced from the primary vertex is performed with the ATLAS detector at the Large Hadron Collider. The search includes the full proton-proton collision dataset collected during Run 2 at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math> and a partial dataset collected during Run 3 in 2022–2023 at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13.6</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>, corresponding to integrated luminosities of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>140</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>56.3</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>, respectively. Final states with displaced electrons or muons are considered, and novel triggers introduced in Run 3 are employed that use large impact parameter tracking to reconstruct displaced tracks with low momentum. In addition, photon reconstruction and multivariate techniques are employed to broaden the sensitivity to channels with large background rates or highly displaced electrons, respectively. The results are consistent with the Standard Model background expectations and are used to set model-independent limits on the production of displaced electrons and muons. The analysis is also interpreted in the context of a gauge-mediated supersymmetry breaking model with pair-produced long-lived sleptons and a dark sector model with pair-produced chargino-like states. The results include 95% confidence level exclusions of selectrons with lifetimes from 4 ps to 60 ns and a mass of 150 GeV, and exclusions of selectrons, smuons, and staus with a lifetime of 0.3 ns for masses up to 740, 830, and 440 GeV, respectively. Dark charginos with masses up to 380 GeV are excluded for a mass difference with the neutral state of 40 GeV, and mass differences down to 17 GeV are excluded for dark charginos with a 100 GeV mass.

France

G. Aad

Norway

E. Aakvaag

United States

B. Abbott

United Arab Emirates

S. Abdelhameed

Germany

K. Abeling

N.J. Abicht

S.H. Abidi

M. Aboelela

Morocco

A. Aboulhorma

Israel

H. Abramowicz

H. Abreu

Y. Abulaiti

Italy

B.S. Acharya

A. Ackermann

C. Adam Bourdarios

Poland

L. Adamczyk

S.V. Addepalli

United Kingdom

M.J. Addison

J. Adelman

Türkiye

A. Adiguzel

T. Adye

A.A. Affolder

Y. Afik

Spain

M.N. Agaras

A. Aggarwal

Romania

C. Agheorghiesei

F. Ahmadov

S. Ahuja

China

X. Ai

G. Aielli

A. Aikot

M. Ait Tamlihat

B. Aitbenchikh

M. Akbiyik

Sweden

T.P.A. Åkesson

A.V. Akimov

Japan

D. Akiyama

N.N. Akolkar

S. Aktas

K. Al Khoury

G.L. Alberghi

Canada

J. Albert

P. Albicocco

G.L. Albouy

S. Alderweireldt

Z.L. Alegria

CERN

M. Aleksa

I.N. Aleksandrov

C. Alexa

Greece

T. Alexopoulos

F. Alfonsi

Switzerland

M. Algren

M. Alhroob

Czechia

B. Ali

H.M.J. Ali

S. Ali

S.W. Alibocus

South Africa

M. Aliev

G. Alimonti

W. Alkakhi

C. Allaire

B.M.M. Allbrooke

J.S. Allen

J.F. Allen

Chile

C.A. Allendes Flores

P.P. Allport

A. Aloisio

Argentina

F. Alonso

C. Alpigiani

Z.M.K. Alsolami

M. Alvarez Estevez

A. Alvarez Fernandez

M. Alves Cardoso

M.G. Alviggi

M. Aly

Brazil

Y. Amaral Coutinho

A. Ambler

C. Amelung

M. Amerl

C.G. Ames

D. Amidei

B. Amini

K. Amirie

Portugal

S.P. Amor Dos Santos

K.R. Amos

D. Amperiadou

S. An

V. Ananiev

C. Anastopoulos

T. Andeen

J.K. Anders

A.C. Anderson

S.Y. Andrean

A. Andreazza

S. Angelidakis

A. Angerami

A.V. Anisenkov

A. Annovi

C. Antel

E. Antipov

Search for displaced leptons in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math> and 13.6 TeV <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>p</mi></math> collisions with the ATLAS detector

Certain supersymmetric elementary string states with angular momentum can be viewed as small black rings in a five-dimensional string theory. These black rings have zero area event horizon. The 4D-5D connection relates these small rings to small black holes without angular momentum in one less dimension. Recent works have proposed saddle solutions that compute the supersymmetric index for small black holes using gravitational path integral. In this paper, we propose an analogous saddle solution for a five-dimensional small black ring. The dominant contribution comes from a black ring saddle that rotates in both independent planes in five dimensions and has a finite area event horizon. We also write the saddle solution as a three center Bena-Warner solution.

India

Subhodip Bandyopadhyay

Gurmeet Punia

Yogesh Srivastava

Amitabh Virmani

The gravitational index of a small black ring

In this study, we implement the type-II seesaw mechanism for Dirac neutrino masses within the framework of a 3-3-1 model. To this end, we introduce a scalar sextet and impose both lepton number conservation and invariance under a discrete $\textit{Z}$ symmetry in the Lagrangian. This mechanism naturally generates small Dirac neutrino masses by allowing the soft breaking of the $\textit{Z}$ symmetry through a unique term in the scalar potential, while preserving lepton number. Specifically, we explore the realization of this model at low-energy scales. Regarding flavor implications, we analyze its contributions to the rare decay processes $\textit{μ}$ → $\textit{eγ}$ and $$ \mu \to \overline{e} ee $$ . In the cosmological context, we analyze the influence of right-handed neutrinos on the effective number of neutrino species, $\textit{N}$ , through interactions mediated by the $\textit{Z}$ boson. Our findings establish a lower bound of $$ {m}_{Z^{\prime }} $$ > 4.4 TeV, which slightly exceeds the current lower limit set by the Large Hadron Collider (LHC).

Vinícius Oliveira

Patricio Escalona

Lucia Angel

C. Pires

Farinaldo Queiroz

Type-II seesaw mechanism for Dirac neutrinos and its implications on $\textit{N}$

The horizon of black hole is surrounded by the photon sphere and an outside observer cannot easily examine the geometry inside the photon sphere. In this note, we propose a way to investigate the region from dual conformal field theory by making use of AdS/CFT correspondence. We first construct gravastar geometry as an asymptotic anti-de Sitter spacetime, where the region inside the photon sphere is replaced by a horizon-less geometry. It is known that bulk-cone singularities in the retarded Green function in dual conformal field theory can encode the bulk null geodesics. We then compute numerically the retarded Green function from the bulk theory and observe bulk-cone singularities corresponding to null geodesics traveling into the interior region. In this way, we show that it is possible to examine the region inside the photon sphere from bulk-cone singularities of dual conformal field theory.

Taiwan

Heng-Yu Chen

Yasuaki Hikida

Yasutaka Koga

AdS gravastar and bulk-cone singularities

We revisit the thermal leptogenesis scenario in the type-I seesaw framework featuring three heavy Majorana neutrinos with a hierarchical mass spectrum. We focus on low energy observables, specifically the lightest neutrino mass $$m_{\nu }^{\textrm{lightest}}$$ and the neutrinoless double-beta decay effective mass parameter $$m^{\textrm{eff}}_{\beta \beta }$$ . In particular, we numerically calculate the minimum mass of the lightest heavy Majorana neutrino, $$M_1^{\textrm{min}}$$ , required for successful leptogenesis as a function of $$m_{\nu }^{\textrm{lightest}}$$ and $$m_{\beta \beta }^{\textrm{eff}}$$ , considering both normal and inverted light neutrino mass orderings. Flavour effects are taken into account within the flavoured density matrix formalism. We also examine the interplay between fine-tuned cancellations in the seesaw relation and $$M_1^{\textrm{min}}$$ . Recent and forthcoming searches for neutrinoless double-beta decay, along with cosmological probes of the sum of neutrino masses, motivate this analysis, as they can provide key insights into the minimal scale of thermal leptogenesis and its broader implications.

A. Granelli

K. Hamaguchi

M. Ramirez-Quezada

K. Shimada

J. Wada

T. Yokoyama

Insights on the scale of leptogenesis from neutrino masses and neutrinoless double-beta decay

Axions are well-motivated dark matter particles. Many experiments are looking for their experimental evidence. For haloscopes, the problem reduces to the identification of a peak above a noisy baseline. Its modeling, however, may be problematic. State-of-the-art analyses rely on the Savitzky-Golay (SG) filtering, which is intrinsically affected by any possible over fluctuation, leading to biased results. In this paper we study the efficiency that different extensions of SG can provide in the peak reconstruction in a standard haloscope-like experiment. We show that, once the correlations among bins are taken into account, there is no appreciable difference. The standard SG remains the advisable choice because of its numerical efficiency.

A. Rosso

J. Conrad

J. Jeong

Baseline filtering and peak reconstruction for haloscope-like axion searches

A quantum theory of asymptotically flat spacetimes is presented using the solutions of the null surface formulation (NSF) field equations in a perturbative scheme. Free-field commutation relations are given for the null free data of NSF at future or past null infinity, and the main variables of NSF are then used to define the interior points of the spacetime as labels and the metric of the spacetime as a derived quantum operator. A nontrivial scattering of gravitons is given.

Carlos N. Kozameh

Lautaro Zapata-Altuna

Quantum theory of asymptotically flat spacetimes

A new framework, called x-scape, for the combined study of both hard and soft transverse momentum sectors in high-energy proton-proton (<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mtext>−</mtext><mi>p</mi></mrow></math>) and proton-nucleus (<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mtext>−</mtext><mi>A</mi></mrow></math>) collisions is set up. A dynamical initial state is set up using the 3d-Glauber model with transverse locations of hotspots within each incoming nucleon. A hard scattering that emanates from two colliding hotspots is carried out using the Pythia generator. Initial state radiation from the incoming hard partons is carried out in a new module called I-matter, which includes the longitudinal location of initial splits. The energy-momentum of both the initial hard partons and their associated beam remnants is removed from the hot spots, depleting the energy-momentum available for the formation of the bulk medium. Outgoing showers are simulated using the matter generator, and results are presented for both cases, allowing for and not allowing for energy loss. First comparisons between this hard-soft model and single inclusive hadron and jet data from <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mtext>−</mtext><mi>p</mi></mrow></math> and minimum bias <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mtext>−</mtext><mtext>Pb</mtext></mrow></math> collisions are presented. Single hadron spectra in <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mtext>−</mtext><mi>p</mi></mrow></math> are used to carry out a limited (in number of parameters) Bayesian calibration of the model. Fair comparisons with data are indicative of the utility of this new framework. Theoretical studies of the correlation between jet <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>p</mi><mi>T</mi></msub></math> and event activity at mid and forward rapidity are carried out.