The positive and negative energy modes of a field theory in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>κ</mi></math>-Minkowski/<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>κ</mi></math>-Poincaré noncommutative spacetime have very different symmetry properties. This can be understood geometrically by considering that they span two distinct sectors of a curved momentum space. By performing an explicit direct computation of the relativistic Noether charges and their algebra within the canonical formalism, we identify a striking consequence of this asymmetry in momentum space: charge conjugation and Poincaré invariance are incompatible. We then notice how the structure of momentum space suggests that time reversal could be deformed so that the overall <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">C</mi><mi mathvariant="script">P</mi><mi mathvariant="script">T</mi></math>-invariance is restored. We prove that this new proposal works by studying the transformation properties under deformed discrete symmetries of the new relativistic charges.

Poland

Tadeusz Adach

Andrea Bevilacqua

Jerzy Kowalski-Glikman

Italy

Giacomo Rosati

Asymmetry in momentum space: Restoring <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">C</mi><mi mathvariant="script">P</mi><mi mathvariant="script">T</mi></math> invariance of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>κ</mi></math>-field theory

Large-momentum effective theory is a physics-guided systematic expansion to calculate light-cone parton distributions, including collinear (PDFs) and transverse-momentum-dependent ones, at any fixed momentum fraction <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>x</mi></math> within a range of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">[</mo><msub><mi>x</mi><mi>min</mi></msub><mo>,</mo><msub><mi>x</mi><mi>max</mi></msub><mo stretchy="false">]</mo></math>. It theoretically solves the ill-posed inverse problem that afflicts other theoretical approaches to collinear PDFs, such as short-distance factorizations. Recently, Dutrieux et al. raised practical concerns about whether current or even future lattice data will have sufficient precision in the subasymptotic correlation region to support an error-controlled extrapolation—and if not, whether it becomes an inverse problem where the relevant uncertainties cannot be properly quantified. While we agree that not all current lattice data have the desired precision to qualify for an asymptotic extrapolation, some calculations do, and more are expected in the future. We comment on the analysis and results in Dutrieux et al. and argue that a physics-based systematic extrapolation still provides the most reliable error estimates, even when the data quality is not ideal. In contrast, reframing the long-distance asymptotic extrapolation as a data-driven-only inverse problem with ad hoc mathematical conditioning could lead to unnecessarily conservative errors.

Taiwan

Jiunn-Wei Chen

United States

Xiang Gao

Jinchen He

China

Jun Hua

Xiangdong Ji

Germany

Andreas Schäfer

Yushan Su

Wei Wang

Yi-Bo Yang

Jian-Hui Zhang

Qi-An Zhang

Rui Zhang

Yong Zhao

Large-momentum effective theory’s asymptotic extrapolation vs the inverse problem

In this manuscript, we study the general scalar leptoquark contributions to the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>g</mi><mi>g</mi><mo stretchy="false">→</mo><mi>Z</mi><mi>h</mi></math> process at a one-loop level. We find that the contributions only show up for the off diagonal Higgs and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi></math> boson interactions with scalar leptoquarks, which can lead to new tensor structures different from the standard model. In the one-field and two-field models, the contributions vanish exactly; thus, the contributions are possible at least in the three-field models. We exemplify the contributions in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>S</mi><mn>1</mn></msub><mo>+</mo><msub><mover accent="true"><mi>R</mi><mo stretchy="false">˜</mo></mover><mn>2</mn></msub><mo>+</mo><msub><mi>S</mi><mn>3</mn></msub></math> model, which can appear in the presence of scalar leptoquark mass splittings and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation. In view of the heavy scalar leptoquark mass suppression, the leading contributions are typically small and difficult to observe at hadron colliders. However, this work offers a quantitative and systematic investigation of scalar leptoquark contributions, also making it valuable for the new physics studies in other models.

Shi-Ping He

Scalar leptoquark contributions to the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>g</mi><mi>g</mi><mo stretchy="false">→</mo><mi>Z</mi><mi>h</mi></math> process

We present a comprehensive study of the screening masses of vector and axial-vector mesons and their corresponding diquark partners within a symmetry-preserving vector-vector contact interaction approach. Our analysis includes mesons and diquarks composed of both light and heavy quarks, providing a unified description of their thermal behavior. The longitudinal and transverse modes of the screening masses are analyzed, and the results are systematically compared with other theoretical approaches. At <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi><mo>=</mo><mn>0</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi></math>, our predictions agree with available experimental data, and a comparison with the expected free theory limit at high temperatures is also presented. Notably, the parity partners of the lightest mesons and diquarks converge at high temperatures, signaling chiral symmetry restoration within this framework. These results provide a consistent and detailed picture of meson and diquark properties at finite temperature and lay the groundwork for extending the capabilities of the model to baryon screening masses in the quark-diquark picture.

Mexico

L.X. Gutiérrez-Guerrero

M.A. Ramírez-Garrido

M.A. Pérez de León

R.J. Hernández-Pinto

Unified analysis of screening masses for vector and axial-vector mesons and their diquark partners in the contact interaction model

Light QCD axions, introduced to solve the strong <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> problem, may form condensates inside neutron stars, giving rise to a novel ground state of dense matter. We investigate how such axion condensates modify the equilibrium structure and radial oscillation spectrum of neutron stars. Using a realistic neutron star model with the BSk26 equation of state, and solving the coupled Tolman-Oppenheimer-Volkoff and Klein-Gordon equations together with a linear perturbation analysis, we find two distinct families of quasinormal modes: weakly damped fluid-dominated oscillations and highly damped axion modes. The coupling between the fluid and the axion field introduces axion-induced damping of radial oscillations, with decay timescales of order seconds for kHz axion masses. Modes with frequencies above the axion mass are strongly damped, while those below remain unaffected. Although neutron star radial oscillations are difficult to observe, our results suggest that extensions of this work can turn neutron star seismology into a novel probe of the axion properties.

Spain

Antonio Gómez-Bañón

Pantelis Pnigouras

José A. Pons

Axion condensates in neutron stars and radial oscillation modes

The dynamics of a light fermion bound to a heavy one is expected to be described by the Dirac equation with an external potential. The potential breaks translation invariance, whereas the bound state momentum is well defined. Boosting the bound state determines the frame dependence of the light fermion dynamics. I study the Dirac limit of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>QCD</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math> in the limit of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mi>c</mi></msub><mo stretchy="false">→</mo><mi>∞</mi></math>. The light quark wave function turns out to be independent of the frame of the bound state, up to an irrelevant Lorentz contraction. The discrete bound state spectrum determines corresponding discrete energies of the Dirac equation, which for a linear potential allows a continuous spectrum.

Finland

Paul Hoyer

Dirac states from the ’t Hooft model

Black holes, as characterized by the Hawking effect and Bekenstein-Hawking entropy, can be treated as a compact object carrying nontrivial quantum information obscured behind the event horizon. This quantum information, while hidden behind the event horizon, can be indirectly probed through the black hole’s interactions with surrounding quantum fields. In this paper, we investigate how the quantum nature of a black-hole influences the correlations harvested by a pair of static Unruh-DeWitt (UDW) detectors. To provide a comprehensive analysis, we employ various correlation measures: concurrence, quantum discord, and the violation of Bell’s inequality, thereby shedding light on the quantum nature of the black hole as perceived by local probes. By treating the black hole as a tidally deformable thermal body under the quantum fluctuation of the mediator fields, as observed by Goldberger and Rothstein [<a href="http://dx.doi.org/10.1007/JHEP04(2020)056">J. High Energy Phys. 04 (2020) 056</a>; <a href="http://dx.doi.org/10.1103/PhysRevLett.125.211301">Phys. Rev. Lett. 125, 211301 (2020)</a>] and Biggs and Maldacena [<a href="http://arXiv.org/abs/2405.02227">arXiv:2405.02227</a>], we employ a post-Newtonian effective field theory (PN-EFT) to derive the final states of the two UDW probes analytically. A key advantage of our approach is the ability to analytically derive all these correlation measures without encountering the complicated Matsubara sum of infinite thermal poles, as in the conventional approach based on quantum fields in curved spacetime. By tuning the relative strengths in the action of PN-EFT, we can extract the effects of the black hole on the entanglement harvesting, quantum correlation, and nonlocality bound of the UDW probe systems. Furthermore, our PN-EFT approach can be extended in future studies to include backreaction on black holes by accounting for higher-order PN corrections.

Feng-Li Lin

Chile

Sayid Mondal

Post-Newtonian effective field theory approach to entanglement harvesting, quantum discord, and Bell’s nonlocality bound near a black hole

Most existing and proposed high-energy neutrino experiments have excellent muon charge identification capabilities, enabling the distinction of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ν</mi><mi>μ</mi></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mover accent="true"><mi>ν</mi><mo stretchy="false">¯</mo></mover><mi>μ</mi></msub></math> charged current interactions. In contrast, distinguishing electrons and positrons from <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ν</mi><mi>e</mi></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mover accent="true"><mi>ν</mi><mo stretchy="false">¯</mo></mover><mi>e</mi></msub></math> interactions is typically impossible, as they quickly interact within the characteristically dense detector material and fail to reach the spectrometer. In this letter, we propose a compact and cost-effective plastic target, placed right before the spectrometer, to maximize the rate of electrons and positrons that reach the spectrometer before interacting. We demonstrate that, when installed at the FASER experiment, the Forward Physics Facility, or SHiP, this setup could enable the first separate measurement of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ν</mi><mi>e</mi></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mover accent="true"><mi>ν</mi><mo stretchy="false">¯</mo></mover><mi>e</mi></msub></math> cross sections at high energy. Additionally, this setup opens new opportunities to study forward particle production at collider neutrino experiments, such as constraining forward <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Λ</mi></math> hyperon production, and, by reducing flux uncertainties, significantly improve limits on nonstandard neutrino interactions in neutral currents.

Felix Kling

Toni Mäkelä

United Kingdom

Josh McFayden

Antielectron neutrinos at high-energy neutrino experiments: Identification strategies and physics potential

In this paper, we propose an experiment, LANSCE-mQ, aiming to detect fractionally charged and millicharged particles (mCPs) using an 800 MeV proton beam fixed target at the Los Alamos Neutron Science Center (LANSCE) facility at Los Alamos National Laboratory. This search can shed new light on numerous fundamental questions, including charge quantization, the predictions of string theories and grand unification theories, the gauge symmetry of the Standard Model, dark sector models, and the tests of cosmic reheating. We propose to install two-layer scintillation detectors made of plastic (such as EJ-200) or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>CeBr</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow></math> to search for mCPs. Dedicated geant4 detector simulations and in situ measurements have been conducted to obtain a preliminary determination of the background rate. The dominant backgrounds are beam-induced neutrons and coincident dark current signals from the photomultiplier tubes, while beam-induced high-energy photons (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi></math>’s) and cosmic muons are subdominant. We determined that LANSCE-mQ, the dedicated mCP experiment, has the leading mCP sensitivity for mass between <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>∼</mo><mn>1</mn></math> and 300 MeV.

Yu-Dai Tsai

South Korea

Insung Hwang

Ryan Schmitz

Matthew Citron

Kranti Gunthoti

Jacob Steenis

Hoyong Jeong

Hyunki Moon

Jae Hyeok Yoo

Ming Xiong Liu

Proposal for a dedicated search for millicharged and fractionally charged particles at LANL

Within the method of parity-projected QCD sum rules, we study the mass spectra of light hybrid baryons with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>I</mi><mo stretchy="false">(</mo><msup><mi>J</mi><mi>P</mi></msup><mo stretchy="false">)</mo><mo>=</mo><mn>1</mn><mo>/</mo><mn>2</mn><mo stretchy="false">(</mo><mn>1</mn><mo>/</mo><msup><mn>2</mn><mo>±</mo></msup><mo stretchy="false">)</mo><mo>,</mo><mn>3</mn><mo>/</mo><mn>2</mn><mo stretchy="false">(</mo><mn>1</mn><mo>/</mo><msup><mn>2</mn><mo>±</mo></msup><mo stretchy="false">)</mo><mo>,</mo><mn>1</mn><mo>/</mo><mn>2</mn><mo stretchy="false">(</mo><mn>3</mn><mo>/</mo><msup><mn>2</mn><mo>±</mo></msup><mo stretchy="false">)</mo><mo>,</mo><mn>3</mn><mo>/</mo><mn>2</mn><mo stretchy="false">(</mo><mn>3</mn><mo>/</mo><msup><mn>2</mn><mo>±</mo></msup><mo stretchy="false">)</mo></math> by constructing the local <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>q</mi><mi>q</mi><mi>q</mi><mi>g</mi></math> interpolating currents. We calculate the correlation functions up to dimension eight condensates at the leading order of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>α</mi><mi>s</mi></msub></math>. The stable QCD Lapalce sum rules can be established for the positive-parity <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mrow><mn>1</mn><mo>/</mo><msup><mn>2</mn><mo>+</mo></msup></mrow></msub><mo>,</mo><msub><mi mathvariant="normal">Δ</mi><mrow><mn>3</mn><mo>/</mo><msup><mn>2</mn><mo>+</mo></msup></mrow></msub><mo>,</mo><msub><mi mathvariant="normal">Δ</mi><mrow><mn>1</mn><mo>/</mo><msup><mn>2</mn><mo>+</mo></msup></mrow></msub></math> and negative-parity <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mrow><mn>1</mn><mo>/</mo><msup><mn>2</mn><mo>−</mo></msup></mrow></msub><mo>,</mo><msub><mi>N</mi><mrow><mn>3</mn><mo>/</mo><msup><mn>2</mn><mo>−</mo></msup></mrow></msub><mo>,</mo><msub><mi mathvariant="normal">Δ</mi><mrow><mn>1</mn><mo>/</mo><msup><mn>2</mn><mo>−</mo></msup></mrow></msub></math> channels to extract their mass spectra. The lowest-lying hybrid baryons are predicted to be the positive-parity <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mrow><mn>1</mn><mo>/</mo><msup><mn>2</mn><mo>+</mo></msup></mrow></msub></math> state around 2.01 GeV. These hybrid baryons mainly decay into conventional baryon plus meson final states. We propose to search for the light hybrid baryons through the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">ϒ</mi><mo>/</mo><mi>ψ</mi><mo stretchy="false">(</mo><mn>3686</mn><mo stretchy="false">)</mo></math> decays via the three-gluon emission mechanism in BESIII and BelleII experiments. Hopefully, our studies of the light hybrid baryons will be useful for understanding the excited baryon spectrum and the behavior of gluonic degrees of freedom in QCD.