Using <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> collision data corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>10.6</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> collected at center-of-mass energies between 4.258 and 4.681 GeV with the BESIII detector at the BEPCII collider, we search for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>1</mn><mrow><mo>−</mo><mo>+</mo></mrow></msup></math> charmoniumlike hybrid via <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><mo stretchy="false">→</mo><mi>γ</mi><mi>η</mi><msub><mi>η</mi><mi>c</mi></msub></math> and <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><mo stretchy="false">→</mo><mi>γ</mi><msup><mi>η</mi><mo>′</mo></msup><msub><mi>η</mi><mi>c</mi></msub></math> decays for the first time. No significant signal is observed, and the upper limits on the Born cross sections for both processes are set at the 90% confidence level.

China

M. Ablikim

Russia

M.N. Achasov

Sweden

P. Adlarson

X.C. Ai

Germany

R. Aliberti

Italy

A. Amoroso

Q. An

Y. Bai

JINR

O. Bakina

Y. Ban

H.R. Bao

Poland

V. Batozskaya

Mongolia

K. Begzsuren

N. Berger

M. Berlowski

M. Bertani

D. Bettoni

F. Bianchi

E. Bianco

A. Bortone

I. Boyko

United States

R.A. Briere

A. Brueggemann

H. Cai

M.H. Cai

X. Cai

A. Calcaterra

G.F. Cao

N. Cao

Türkiye

S.A. Cetin

X.Y. Chai

J.F. Chang

G.R. Che

Y.Z. Che

C.H. Chen

Chao Chen

G. Chen

H.S. Chen

H.Y. Chen

M.L. Chen

S.J. Chen

S.L. Chen

S.M. Chen

T. Chen

X.R. Chen

X.T. Chen

X.Y. Chen

Y.B. Chen

Y.Q. Chen

Z.J. Chen

Z.K. Chen

South Korea

S.K. Choi

X. Chu

G. Cibinetto

F. Cossio

United Kingdom

J. Cottee-Meldrum

J.J. Cui

H.L. Dai

J.P. Dai

A. Dbeyssi

R.E. de Boer

D. Dedovich

C.Q. Deng

Z.Y. Deng

A. Denig

I. Denysenko

M. Destefanis

F. De Mori

B. Ding

X.X. Ding

Y. Ding

Y.X. Ding

J. Dong

L.Y. Dong

M.Y. Dong

X. Dong

M.C. Du

S.X. Du

Y.Y. Duan

P. Egorov

G.F. Fan

J.J. Fan

Y.H. Fan

J. Fang

S.S. Fang

W.X. Fang

Y.Q. Fang

R. Farinelli

L. Fava

F. Feldbauer

G. Felici

C.Q. Feng

J.H. Feng

L. Feng

Q.X. Feng

Y.T. Feng

Search for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>1</mn><mrow><mo>−</mo><mo>+</mo></mrow></msup></math> charmoniumlike hybrid via <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup><mo stretchy="false">→</mo><mi>γ</mi><msup><mrow><mi>η</mi></mrow><mrow><mo stretchy="false">(</mo><mo>′</mo><mo stretchy="false">)</mo></mrow></msup><msub><mrow><mi>η</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math> at center-of-mass energies between 4.258 and 4.681 GeV

We perform a systematical investigation of the doubly charmed dibaryon system with quantum numbers <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>I</mi><mi>J</mi><mo>=</mo><mn>01</mn></math> and strangeness numbers <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mo>=</mo><mn>0</mn></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>−</mo><mn>2</mn></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>−</mo><mn>4</mn></math> in the framework of the chiral quark model. Two resonance states with strangeness numbers <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mo>=</mo><mo>−</mo><mn>2</mn></math> are obtained in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Λ</mi><msub><mi mathvariant="normal">Ω</mi><mrow><mi>c</mi><mi>c</mi></mrow></msub></math> scattering channel: the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="normal">Ξ</mi><mrow><mi>c</mi><mi>c</mi></mrow><mo>*</mo></msubsup><mi mathvariant="normal">Ξ</mi></math> state with resonance mass 5081 MeV and decay width 0.3 MeV, and the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="normal">Ξ</mi><mi>c</mi><mo>*</mo></msubsup><msubsup><mi mathvariant="normal">Ξ</mi><mi>c</mi><mo>′</mo></msubsup></math> state with mass 5213 MeV and decay width 19.8 MeV. These two predicted charmed dibaryon candidates are worth searching for experimentally. Besides this, we would like to emphasize that the multichannel coupling calculation is important for confirming the existence of multiquark states. The coupling can shift the energy of the resonance, give width to the resonance, and even destroy the resonance. Therefore, to provide the necessary information for experiments to search for exotic hadron states, the coupling calculation between the bound channels and open channels is indispensable.

Yao Cui

Yuheng Wu

Xinmei Zhu

Hongxia Huang

Jialun Ping

Search for doubly charmed dibaryons in baryon-baryon scattering

We have addressed here the problem of calculating the correlation function of a stable particle with a resonance, in particular one resonance that qualifies as a molecular state of two components. The formalism used requires us to evaluate the scattering matrix of the stable particle with the molecule, a nuclear problem which we address by means of the fixed center approximation. We have applied the method to the interaction of a proton with the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>f</mi><mn>1</mn></msub><mo stretchy="false">(</mo><mn>1285</mn><mo stretchy="false">)</mo></math> resonance, presently under investigation by the ALICE collaboration, where the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>f</mi><mn>1</mn></msub><mo stretchy="false">(</mo><mn>1285</mn><mo stretchy="false">)</mo></math> is taken as a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mo>*</mo></msup><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mo>−</mo><msup><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mo>*</mo></msup><mi>K</mi></math> molecule. We find that the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><msub><mi>f</mi><mn>1</mn></msub><mo stretchy="false">(</mo><mn>1285</mn><mo stretchy="false">)</mo></math> interaction develops a resonance state below the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><msub><mi>f</mi><mn>1</mn></msub><mo stretchy="false">(</mo><mn>1285</mn><mo stretchy="false">)</mo></math> threshold, which leads to a depletion in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><msub><mi>f</mi><mn>1</mn></msub><mo stretchy="false">(</mo><mn>1285</mn><mo stretchy="false">)</mo></math> correlation function for small values of the proton momentum. The discussion presented shows that these type of studies can provide much information on the nature of some resonances and the existence of three-body bound states involving mesons and baryons.

Spain

P. Encarnación

A. Feijoo

E. Oset

Correlation function for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>p</mi><msub><mrow><mi>f</mi></mrow><mrow><mn>1</mn></mrow></msub><mo stretchy="false">(</mo><mn>1285</mn><mo stretchy="false">)</mo></mrow></math> interaction

We show how certain types of magnetic asymptotically anti–de Sitter Euclidean wormholes can catalyze the onset of inflation. These wormholes can be embedded as saddle point solutions of general relativity coupled to the Standard Model, the inflaton being identified with the Higgs particle. Our scenario is based on the assumption that the quantum effective potential for the Higgs turns negative at a certain high energy window, in line with current measured values for the Higgs and top quark masses. Within our proposal, we can estimate various parameters and physical quantities of interest, in consistency with current observational bounds.

Belgium

Panos Betzios

Estonia

Ioannis D. Gialamas

France

Olga Papadoulaki

Magnetic anti–de Sitter wormholes as seeds for Higgs inflation

We study a simplified model of two colourless heavy vector resonances in the singlet representation of SU(2) , with zero and unit hypercharge. We discuss mixing with the Standard Model gauge bosons due to electroweak symmetry breaking, semi-analytic formulae for production at proton colliders, requirements to obey the narrow width approximation and selected low energy constraints. We show current LHC constraints and sensitivity projections for the HL-LHC, HE-LHC, SPPC and FCC-hh on the charged and neutral heavy vectors. The utility of the simplified model Lagrangian is demonstrated by matching these results onto three explicit models: a weakly coupled abelian extension of the Standard Model gauge group, a weakly coupled non-abelian extension and a strongly coupled minimal composite Higgs model. All our results are presented in terms of physical resonance masses, using expressions which are accurate even at vector masses near the electroweak scale due to a parameter inversion we derive. We discuss the importance of this inversion and point out that its effect, and the effects of electroweak symmetry breaking, can remain important up to resonance masses of several TeV. Finally, we clarify the relation between this simplified model and the Heavy Vector Triplet (HVT) model, a simplified model for heavy SU(2) triplets with zero hypercharge, and provide exact and approximate matching relations.

Michael Baker

Timothy Martonhelyi

Andrea Thamm

Riccardo Torre

A simplified model of Heavy Vector Singlets for the LHC and future colliders

We derive a general formalism that relates the spectrum of two-particle systems in a finite volume to physical scattering amplitudes, taking into account the presence of any left-hand branch cuts due to single-particle exchanges. The method first relates the finite-volume spectrum to an infinite-volume short-range quantity, denoted $$ {\mathcal{M}}_0 $$ , and then relates the latter to the physical scattering amplitudes via known integral equations. The derivation of both relations is performed using all-orders perturbation theory and is exact up to neglected exponentially suppressed volume dependence. The relations hold for arbitrary two-particle systems with any number of coupled channels, non-identical and non-degenerate particles, and any intrinsic spin.

André Raposo

Raul Briceño

Maxwell Hansen

Andrew Jackura

Extracting scattering amplitudes for arbitrary two-particle systems with one-particle left-hand cuts via lattice QCD

We present strategies for the $\textit{Mu3e}$ experiment to search for light, weakly coupled particles produced in rare muon decays, focusing on displaced $\textit{e}$ $\textit{e}$ decays within the hollow target. In most scenarios the backgrounds can be fully suppressed with a suitable set of cuts. We furthermore quantify the interplay between displaced and prompt searches at $\textit{Mu3e}$ and existing constraints, showing how $\textit{Mu3e}$ has a unique opportunity to probe unexplored parameter space.

Simon Knapen

Toby Opferkuch

Diego Redigolo

Michele Tammaro

Displaced searches for Axion-Like Particles and Heavy Neutral Leptons at Mu3e

Due to Heisenberg’s uncertainty principle, atomic electrons localized around the nucleus exhibit a characteristic momentum distribution that, in elements with high atomic number, remains significant up to relativistic values. Consequently, in fixed-target experiments, atoms can effectively act as electron accelerators, increasing the centre-of-mass energy in collisions with beam particles. In this work, we leverage this effect to explore its potential for new physics searches. We consider positrons from beams of various energies annihilating with atomic electrons in a W fixed target. We compute the production rates of new vector bosons and pseudoscalar particles as functions of their couplings and masses. We show that the electron-at-rest approximation significantly underestimates the mass reach for producing these new states compared to the results obtained by properly accounting for atomic electron momenta. In particular, we estimate the sensitivity for detecting these new particles using the positron beam at the Beam Test Facility linac at the Laboratori Nazionali di Frascati, the H4 beamline in the CERN North Area, and the proposed Continuous Electron Beam Accelerator Facility of Jefferson Laboratory.

Fernando Arias-Aragón

Giovanni Grilli di Cortona

Enrico Nardi

Léo Veissière

Atoms as electron accelerators for new physics searches

We present efficient algorithms for obtaining the Hamiltonian in Lightcone Conformal Truncation (LCT) for a 2d scalar field with a generic potential. We apply this method to the sine-Gordon and sinh-Gordon models in 1 +1$\textit{d}$, and find precise agreement with integrability results when the scaling dimension ∆ of the deforming cosine/cosinh potential is in the range ∆ ≤ 1. The agreement provides additional evidence for a recent conjecture for how to compute the effective lightcone Hamiltonian in this class of models. In addition, to high precision, we provide the first direct confirmation for the conjectured self-duality of the sinh-Gordon model (∆ < 0), which relates ∆ ↔ 4/∆. As the dimension approaches the upper limit ∆ = 1 from below, we show analytically that the Hamiltonian matrix elements exactly reproduce those of a free Majorana fermion, demonstrating how bosonization is manifested in the LCT basis. We comment on the possible extension of the approach to ∆ > 1.

A. Fitzpatrick

Emanuel Katz

Yuan Xin

Toolkit for general 2d scalar potential in LCT

The influence of a dark energy fluid on the equation of state of neutron stars is investigated. A detailed analysis is conducted for such models, including the computation of the moment of inertia, the quadrupole moment, and the tidal Love number. The results demonstrate that these quantities are interconnected through the well-known equation of state independent I-Love-Q relations. This work extends the applicability of these universal relations to a broader class of neutron star models.

Simone D’Onofrio

I-Love-Q relations for neutron stars with dark energy