Cosmic strings are powerful witnesses to cosmic events including any period of early matter domination. If such a period of matter domination was catalyzed by metastable, long-lived particles, then there will be complementary signals to ascertain the nature of the dark sector in experiments detecting primordial features in the gravitational wave (GW) power spectrum and laboratory searches for long-lived particles. We give explicit examples of global and local <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi><mo stretchy="false">(</mo><mn>1</mn><mo stretchy="false">)</mo></math> gauge extended dark sectors to demonstrate such a complementarity as the union of the two experiments reveals more information about the dark sector than either experiment. Demanding that Higgs-portal long-lived scalar be looked for, in various experiments such as DUNE, FASER, FASER-II, MATHUSLA, and SHiP, we identify the parameter space that leads to complementary observables for GW detectors such as the Laser Interferometer Space Antenna and Einstein Telescope.

China

Satyabrata Datta

India

Ambar Ghosal

Poland

Anish Ghoshal

United Kingdom

Graham White

Complementarity between cosmic string gravitational waves and long-lived particle searches in a laboratory

In this manuscript we study the exclusive photoproduction of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mi>c</mi></msub><mi>γ</mi></math> pairs in the collinear factorization framework. We found the coefficient functions for all possible spins and helicity projections of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mi>c</mi></msub></math> mesons and final-state photons in the leading order in the strong coupling <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>α</mi><mi>s</mi></msub></math>. In our analysis we focused on the contribution of the leading twist chiral-even generalized parton distributions (GPDs) and found that for all spin states of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mi>c</mi></msub></math> the suggested process is largely determined by the behavior of the gluon GPDs <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>H</mi><mi>g</mi></msub></math>. Using the phenomenological parametrizations of the GPDs from the literature, we estimated numerically the photoproduction cross sections and the expected counting rates in the kinematics of medium-energy photoproduction experiments that could be realized at the Electron-Ion Collider. We observed that the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>c</mi><mn>1</mn></mrow></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>c</mi><mn>2</mn></mrow></msub></math> mesons are produced predominantly with the same polarization as the incoming photon, and the expected counting rates of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>c</mi><mn>1</mn></mrow></msub><mi>γ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>c</mi><mn>2</mn></mrow></msub><mi>γ</mi></math> pairs are sufficiently large for their experimental study. We also analyzed the angular distribution of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mi>c</mi></msub></math> mesons in electroproduction experiments and noticed that for some helicity components there are sizable angular asymmetries, which can be used as complementary observables for experimental study. Finally, we estimated the role of this process as a potential background to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mi>c</mi></msub></math> photoproduction, which has been recently suggested as a tool for studies of odderons. We found that the contribution of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mi>c</mi></msub><mi>γ</mi></math> (with undetected photon) is on par with expected contributions of odderons and Primakoff mechanisms in the kinematics of small momentum transfer <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><mi>t</mi><mo stretchy="false">|</mo><mo>≲</mo><mn>1</mn><mtext> </mtext><mtext> </mtext><msup><mrow><mi>GeV</mi></mrow><mrow><mn>2</mn></mrow></msup></math>, but becomes negligible at larger <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><mi>t</mi><mo stretchy="false">|</mo></math>.

Chile

Marat Siddikov

Ivan Zemlyakov

Exclusive photoproduction of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mi>c</mi></msub><mi>γ</mi></math> pairs

Addressing the fermion flavor structures using modular invariance is a challenging task in the framework of quark-lepton unification. Building on recent applications of modular symmetry in nonsupersymmetric models, we propose the first renormalizable <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mi>U</mi><mo stretchy="false">(</mo><mn>5</mn><mo stretchy="false">)</mo></math> grand unified theory incorporating level 3 nonholomorphic modular symmetry, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="normal">Γ</mi><mn>3</mn></msub><mo>≃</mo><msub><mi>A</mi><mn>4</mn></msub></math>. This framework constrains Yukawa couplings to polyharmonic Maaß forms, significantly reducing the number of free parameters while enhancing the predictive power of the models. We present a comprehensive analysis of fermion masses and mixing while tackling key grand unified theory (GUT) queries such as gauge coupling unification and proton decay. Beyond the minimal <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mi>U</mi><mo stretchy="false">(</mo><mn>5</mn><mo stretchy="false">)</mo></math> framework, the Higgs sector incorporates the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>4</mn><msub><mn>5</mn><mi>H</mi></msub></math> dimensional Higgs field crucial in differentiating the masses of down quarks and charged leptons, and the fermion sector is extended with three right-handed neutrinos enabling neutrino masses via the type-I seesaw mechanism. We analyze two benchmark models with distinct modular weight and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>A</mi><mn>4</mn></msub></math> charge assignments. The predicted effective Majorana mass <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mrow><mi>β</mi><mi>β</mi></mrow></msub></math> values align with current neutrinoless double-beta decay experiments, and the effective neutrino mass <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>β</mi></msub></math> is within the reach of future beta decay searches. The predicted sum of neutrino masses, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>∑</mo><msub><mi>m</mi><mi>i</mi></msub></math>, satisfies the upper bound set by recent cosmological observations. The gauge coupling unification is achieved through a light scalar triplet <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ϕ</mi><mn>3</mn></msub><mo>∼</mo><mo stretchy="false">(</mo><mn>3</mn><mo>,</mo><mn>3</mn><mo>,</mo><mo>−</mo><mn>1</mn><mo>/</mo><mn>3</mn><mo stretchy="false">)</mo></math> and a scalar octet <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ϕ</mi><mn>5</mn></msub><mo>∼</mo><mo stretchy="false">(</mo><mn>8</mn><mo>,</mo><mn>2</mn><mo>,</mo><mn>1</mn><mo>/</mo><mn>2</mn><mo stretchy="false">)</mo></math> belonging to the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>4</mn><msub><mn>5</mn><mi>H</mi></msub></math> Higgs, while proton decay constraints require that the contribution of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>4</mn><msub><mn>5</mn><mi>H</mi></msub></math> Higgs to the up-quark mass matrix remains highly suppressed.

United Arab Emirates

Mohamed Amin Loualidi

Morocco

Mohamed Miskaoui

Salah Nasri

Nonholomorphic <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>A</mi><mn>4</mn></msub></math> modular invariance for fermion masses and mixing in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mi>U</mi><mo stretchy="false">(</mo><mn>5</mn><mo stretchy="false">)</mo></math> GUT

The choice of unfolding method for a cross-section measurement is tightly coupled to the model dependence of the efficiency correction and the overall impact of cross-section modeling uncertainties in the analysis. A key issue is the dimensionality used in unfolding, as the kinematics of all outgoing particles in an event typically affect the reconstruction performance in a neutrino detector. OmniFold is an unfolding method that iteratively reweights a simulated dataset, using machine learning to utilize arbitrarily high-dimensional information, that has previously been applied to proton-proton and proton-electron datasets. This paper demonstrates OmniFold’s application to a neutrino cross-section measurement for the first time using a public T2K near detector simulated dataset, comparing its performance with traditional approaches using a mock data study.

United States

R.G. Huang

A. Cudd

Japan

M. Kawaue

T. Kikawa

B. Nachman

V. Mikuni

C. Wilkinson

Machine learning assisted unfolding for neutrino cross-section measurements with the OmniFold technique

We introduce a new approach to modeling transition distribution amplitudes (TDAs) for the processes <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>e</mi><mi>p</mi><mo stretchy="false">→</mo><mi>e</mi><mi>n</mi><msup><mi>π</mi><mo>+</mo></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>e</mi><mi>p</mi><mo stretchy="false">→</mo><mi>e</mi><mi>p</mi><msup><mi>π</mi><mn>0</mn></msup></math>. The modeling is flexible, constrained by sparsely available experimental data, and satisfies theoretical requirements, including reduction to nucleon distribution amplitudes in the appropriate limit. We study the sensitivity of observable predictions to various modeling assumptions. We discuss unpolarized cross sections, as well as the three nonvanishing polarization observables at leading twist, namely, the single transverse target spin asymmetry and the two double spin asymmetries that occur with a polarized lepton beam on either a longitudinally or transversely polarized target. The analysis is complemented by a simple Monte Carlo study to provide guidance for exploring exclusive processes in the so-called backward kinematics. Our work aims to highlight the importance of future measurements to better constrain TDAs and to support upcoming experimental proposals.

France

B. Pire

South Korea

Russia

K. Semenov-Tian-Shansky

P. Sznajder

L. Szymanowski

Toward an advanced phenomenology of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>π</mi><mi>N</mi></math> transition distribution amplitudes

We study the four-body heavy baryon decay, including two leptons in the final state, of the form <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>B</mi></mrow><mrow><mi>A</mi></mrow></msub><mo stretchy="false">→</mo><msub><mrow><mi>B</mi></mrow><mrow><mi>B</mi></mrow></msub><mi>P</mi><msub><mrow><mo>ℓ</mo></mrow><mrow><mi>α</mi></mrow></msub><msub><mrow><mo>ℓ</mo></mrow><mrow><mi>β</mi></mrow></msub></mrow></math>, which can be either a lepton number conserving (LNC) or a lepton number violating (LNV) process (where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>P</mi></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>ℓ</mo></math> are baryons, pseudoscalar mesons, and leptons, respectively), including all kinematic allowed lepton pair possibilities. We work beyond the simplified assumption of a single heavy Majorana neutrino mixing with the active sector, considering potential interference effects when including two nearly degenerate heavy Majorana neutrinos. Particularly, we provide a first estimate of the decay channels involving different flavors for the external leptons (e.g., muon-tau) and elaborate on the interference pattern due to leptons exchange. We show that the results for the two heavy almost degenerate neutrinos can be recast into a single Majorana neutrino and exhibit the features for both the LNC and LNV scenarios. We determine the potential exclusion region for the mass and heavy-light mixing parameters, of the neutrinos driving the decay, including finite size detector effects, and compare them with those from direct searches and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>τ</mi></math> and meson decays. We also obtain the branching ratio as a function of the heavy neutrino mass for the current upper limit of the heavy-light mixings.

Mexico

Fabiola Fortuna

Genaro Toledo

Gerardo Hernández-Tomé

Diego Portillo-Sánchez

Lepton number violating and conserving heavy baryon four-body decays in the presence of two almost degenerate heavy neutrinos

Coherent elastic neutrino-nucleus scattering (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>CE</mi><mi>ν</mi><mi>NS</mi></mrow></math>) is a key process for probing Standard Model and beyond the Standard Model (BSM) properties. Following its first detection by the COHERENT Collaboration, recent reactor-based experiments provide a unique opportunity to refine our current understanding. In particular, the high-precision data from <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>CONUS</mi><mo>+</mo></mrow></math>, combined with the strong bounds from TEXONO, not only validate the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>CE</mi><mi>ν</mi><mi>NS</mi></mrow></math> process at low energies but also provide improved constraints on the weak mixing angle, neutrino electromagnetic properties (including the charge radius, millicharge, and magnetic moment), and nonstandard interactions and light mediators. We also examine the role of elastic neutrino-electron scattering, which gains significance in certain BSM scenarios and allows us to obtain the best limit for the millicharge of the electron neutrinos. By combining reactor and higher-energy spallation neutron source measurements, this work strengthens <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>CE</mi><mi>ν</mi><mi>NS</mi></mrow></math> as a precision tool for testing the Standard Model and beyond.

Italy

M. Atzori Corona

M. Cadeddu

N. Cargioli

F. Dordei

C. Giunti

Reactor antineutrinos <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>CE</mi><mi>ν</mi><mi>NS</mi></mrow></math> on germanium: <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>CONUS</mi><mo>+</mo></mrow></math> and TEXONO as a new gateway to SM and BSM physics

Spin correlation observables of particles produced at colliders generally depend on the coordinate basis. While spin correlations and their associated basis dependence have been studied in top-quark pair production, the basis dependence of spin correlations of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>W</mi><mo>±</mo></msup></math> pairs has not been studied. In this work, we focus on the azimuthal-angle correlation in the decay of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>W</mi><mo>±</mo></msup></math> pairs, which encodes spin information in the direction transverse to the rotational axis. We quantitatively describe the basis dependence of the relative azimuthal angle. We further present the optimal coordinate direction to define the azimuthal angle between the decay products of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>W</mi><mo>±</mo></msup></math> bosons to achieve the maximal spin correlation based on symmetry considerations. The results can be used to optimize the measurement of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math>-even and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math>-odd interactions, and have applications to quantum information observables in the vector boson pair system.

Kun Cheng

Yi-Jing Fang

Tao Han

Matthew Low

Maximizing the azimuthal-angle correlation in the decay of vector boson pairs

Using a symmetry-preserving treatment of a vector <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>×</mo></math> vector contact interaction at nonzero temperature, we compute the screening masses of flavor-SU(3) ground-state <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>J</mi><mi>P</mi></msup><mo>=</mo><msup><mn>0</mn><mo>±</mo></msup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>1</mn><mo>±</mo></msup></math> mesons, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>J</mi><mi>P</mi></msup><mo>=</mo><mn>1</mn><mo>/</mo><msup><mn>2</mn><mo>±</mo></msup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3</mn><mo>/</mo><msup><mn>2</mn><mo>±</mo></msup></math> baryons. We find that all correlation channels allowed at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi><mo>=</mo><mn>0</mn></math> persist when the temperature increases, even above the QCD phase transition temperature. The results for mesons qualitatively agree with those obtained from the contemporary lattice-regularized quantum chromodynamics simulations. One of the most remarkable features is that each parity-partner-pair degenerates when <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi><mo>&gt;</mo><msub><mi>T</mi><mi>c</mi></msub></math>, with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mi>c</mi></msub></math> being the critical temperature. For each pair, the screening mass of the negative parity meson increases monotonously with temperature. In contrast, the screening mass of the meson with positive parity is almost invariant on the domain <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi><mo>≲</mo><msub><mi>T</mi><mi>c</mi></msub><mo>/</mo><mn>2</mn></math>; when <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi></math> gets close to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mi>c</mi></msub></math>, it decreases but soon increases again and finally degenerates with its parity partner, which signals the restoration of chiral symmetry. We also find that the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi></math>-dependent behaviors of baryon screening masses are quite similar to those of the mesons. For baryons, the dynamical, nonpointlike diquark correlations play a crucial role in the screening mass evolution. We further calculate the evolution of the fraction of each kind of diquark within baryons respective to temperature. We observe that, at high temperatures, only <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>=</mo><mn>0</mn></math> scalar and pseudoscalar diquark correlations can survive within <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>J</mi><mi>P</mi></msup><mo>=</mo><mn>1</mn><mo>/</mo><msup><mn>2</mn><mo>±</mo></msup></math> baryons.

Chen Chen

Fei Gao

Si-xue Qin

Screening masses of positive- and negative-parity hadron ground states, including those with strangeness

It is well-known that the momentum spectra of particles confined to finite spatial volumes deviate from the continuous spectra used for unconfined particles. In this article, we consider real scalar particles confined to finite volumes with periodic boundary conditions, such that the particles’ spectra are discrete. We directly compute the density matrices describing the decay processes $$\phi \rightarrow \varphi ^2$$ and $$\phi \rightarrow \varphi \chi \nu $$ , and subsequently derive expressions for the decay probabilities both for confined and unconfined particles. The latter decay process is used as a rough toy model for a neutron decaying into a proton, an electron, and an anti-electron neutrino. We propose that finite volume effects can have an impact on the outcomes of experiments measuring the neutron lifetime. In addition, our findings at the toy model level suggest that taking into account possible initial correlations between neutrons and their daughter particles might be relevant as well.

Austria

Christian Käding

Particles in finite volumes and a toy model of decaying neutrons