Generalised spin structures are necessary for placing fermions on manifolds that do not admit a standard spin structure. This is especially relevant in a dimensional reduction on such a manifold, which can then be compensated by using fermions that are appropriately charged under some Maxwell or Yang-Mills field defined on the internal manifold. A well known example in the physics literature is $$ {\mathbbm{CP}}^2 $$ , which has four real dimensions and is the coset SU(3)/U(2). In this paper we focus on a five-dimensional coset space, namely the Wu manifold SU(3)/SO(3) , where SO(3) is maximal in SU(3). Intriguingly, the Wu manifold does not admit a spin structure or spin structure, it does admit a spin structure. We provide a physical interpretation of the spin structure by considering spinors that are coupled to an SO(3) Yang-Mills field defined on the Wu manifold, but which carry half-integer “isospin,” thereby canceling the minus sign in the holonomy for uncharged spinors that provides the original obstruction to an ordinary spin structure. We also construct a gauge-covariantly constant spinor in the Wu manifold, and we show how this can be employed in order to construct spin spinor harmonics from scalar harmonics. We provide a very explicit construction of all the scalar and spin harmonics. In a follow-up paper, we shall employ the results we obtain here in order to discuss dimensional reductions and consistent reductions on the Wu manifold.

United States

Cameron Gibson

Okan Günel

Gabriel Larios

C. Pope

Spin $\textit{h}$ structure, scalar and charged spinor eigenfunctions on the SU(3)/SO(3) Wu manifold

Motivated by the observation of the doubly charmed tetraquark $ T_{cc}(3875)^+ $ , we present a systematic study of doubly heavy tetraquarks ( $ T_{QQ'\bar{q}\bar{q}'} $ ) using heavy antiquark-diquark symmetry (HADS) within a constituent quark model. By calibrating model parameters to known hadron spectra and incorporating the effective mass formula, we predict the masses for 38 ground-state tetraquarks with $ cc $ , $ bb $ , and $ bc $ heavy quark pairs, including the non-strange, single-strange, and double-strange configurations with quantum numbers $ J^P = 0^+, 1^+ $ and $ 2^+ $ . Notably, we identify several stable states below the relevant meson-meson thresholds, particularly in the $ bb\bar{q}\bar{q}' $ sector. The explicit connection between the doubly heavy tetraquark and the heavy baryon spectra through HADS reduces model dependence and reveals the fundamental systematics in the heavy-quark hadron landscape.

China

Liu-Yu Zhang

Tian-Wei Wu

Yong-Liang Ma

Bridging doubly heavy tetraquark mass spectrum with heavy baryons utilizing heavy antiquark-diquark symmetry * The work of Tian-Wei Wu is supported by the National Natural Science Foundation of China (12405108). Yong-Liang Ma is supported in part by the National Science Foundation of China (NSFC) (12347103) and Gusu Talent Innovation Program (ZXL2024363)

In this work, we demonstrate the complete process of using space-based gravitational wave detectors to measure properties of the stochastic gravitational wave background arising from a first-order electroweak phase transition. Based on frequency-domain simulations of the Taiji mission, including instrumental noise and astrophysical foregrounds, we perform parameter inference using both the Fisher information matrix and Bayesian Markov Chain Monte Carlo sampling. We show how the reconstructed spectrum constrains the macroscopic parameters of the phase transition, and further how these constraints map onto the underlying particle-physics parameters in a singlet-extended Standard Model. Our results demonstrate that the Higgs cubic and quartic self-couplings can be significantly constrained using gravitational wave observations, despite limitations arising from parameter degeneracy.

Japan

Shuo Guan

Huai-Ke Guo

Dian Jiao

Qingyuan Liang

Lei Wu

Yang Zhang

Measuring gravitational wave spectrum from electroweak phase transition and Higgs self-couplings

Millicharged particles are well-motivated dark matter candidates arising in many extensions of the standard model. We show that, despite their tiny coupling <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>e</mi><mi>m</mi></msub></math> to photons, millicharged dark matter (mDM) in the Earth’s geomagnetic field can generate a quasistatic, monochromatic magnetic signal with angular frequency twice the mDM mass. Using null results from the SuperMAG and SNIPE Hunt collaborations, we constrain the effective charge of bosonic mDM in the mass range <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>18</mn></mrow></msup><mo>−</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>14</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi></mrow></math>. The resulting upper bounds exceed stellar cooling constraints by over 13 orders of magnitude, demonstrating the power of this method.

Ariel Arza

Yuanlin Gong

Jing Shu

Qiang Yuan

Bin Zhu

Geomagnetic Constraints on Millicharged Dark Matter

Axionlike particles (ALPs), hypothetical particles beyond the Standard Model (SM), are considered as promising dark matter candidates. ALPs can convert into photons and vice versa in a magnetic field via the Primakoff effect, potentially generating detectable oscillation in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi></math>-ray spectra. This study analyzes 16.5 years of data from the Fermi Large Area Telescope (Fermi-LAT) on NGC 1275, the brightest galaxy in the Perseus cluster, to constrain the ALP parameter space. Our results improve the previous 95% exclusion limits of the photon-ALP coupling <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>g</mi><mrow><mi>a</mi><mi>γ</mi></mrow></msub></math> by a factor of 2 in the ALP mass range of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>4</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>10</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi><mo>≲</mo><msub><mi>m</mi><mi>a</mi></msub><mo>≲</mo><mn>5</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>9</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi></math>. Moreover, we investigate the projected sensitivity of the future Very Large Area <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi></math>-ray Space Telescope (VLAST) on searching for ALPs. We find that (i) the expected sensitivity on the photon-ALP coupling <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>g</mi><mrow><mi>a</mi><mi>γ</mi></mrow></msub></math> can be stronger than that from the upcoming International Axion Observatory in the ALP mass range of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>11</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi><mo>≲</mo><msub><mi>m</mi><mi>a</mi></msub><mo>≲</mo><mn>1</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi></math>, with the best sensitivity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>g</mi><mrow><mi>a</mi><mi>γ</mi></mrow></msub><mo>∼</mo><mn>7</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>13</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>GeV</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>a</mi></msub><mo>∼</mo><mn>2</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>10</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi></math>; (ii) VLAST can extend the sensitivity of the ALP masses below <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>5</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>12</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi></math>, where the photon-ALP coupling <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>g</mi><mrow><mi>a</mi><mi>γ</mi></mrow></msub><mo>≳</mo><mn>1.5</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>11</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>GeV</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> will be excluded; (iii) the entire parameter space of ALP accounting for TeV transparency can be fully tested. These results demonstrate that VLAST will offer an excellent opportunity for ALPs searches.

Zhi-Qi Guo

Yue-Lin Sming Tsai

Zi-Qing Xia

Constraints on axionlike particles from 16.5 years of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>F</mi><mi>e</mi><mi>r</mi><mi>m</mi><mi>i</mi></math>-LAT data and prospects for VLAST

We explore the supernova neutrino-boosted dark matter (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>SN</mi><mi>ν</mi><mi>BDM</mi></mrow></math>) and its direct detection. During core-collapse supernova, an abundance of neutrinos are emitted. These supernova neutrinos can transfer their kinetic energy to the light dark matter via their interactions, and thus are detected in the neutrino and dark matter experiments. Because of the exponential suppression of the high-energy neutrino flux, the kinetic energy carried by a large portion of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>SN</mi><mi>ν</mi><mi>BDM</mi></mrow></math> falls within the MeV range. We consider a simplified model where dark matter interacts with both electrons and neutrinos through a light mediator. In this case, the enhancement in the scattering rate from the light mediator combined with the excitation of the plasmon resonance in silicon significantly enhances the sensitivity in experiments using low-threshold detectors, such as skipper CCDs, in contrast to conventional neutrino and dark matter direct-detection experiments. We calculate the total scattering rate induced by <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>SN</mi><mi>ν</mi><mi>BDM</mi></mrow></math> and derive exclusion limits from Super-K, XENON1T, SENSEI, and DAMIC-M.

Jun-Wei Sun

Yan-Hao Xu

Probing supernova neutrino boosted dark matter with collective excitations

We study the transverse momentum ( $p_T$ ) differential anisotropic flow and flow fluctuation in Pb+Pb collisions at $\sqrt{s_{_{NN}}}$ =5.02 TeV at the LHC. A (3+1)-dimensional CLVisc hydrodynamics framework with fluctuating TRENTO (or AMPT) initial conditions is utilized to simulate the space-time evolution of the quark-gluon plasma (QGP) medium. The effects of shear viscosity and the sub-nucleon structure on anisotropic flow and flow fluctuation are analyzed. Our result shows that shear viscosity tends to suppress both flow coefficients ( ${v_2\{2}\}$ , ${v_2\{4\}}$ , and ${\langle v_2\rangle}$ ) and flow fluctuation ( ${\sigma_{v_2}}$ ) owing to its smearing effect on local density fluctuation. The flow coefficients appear to be insensitive to the sub-nucleon structure, whereas the flow fluctuation ${\sigma_{v_2}}$ tends to be suppressed by the sub-nucleon structure in central collisions but enhanced in peripheral collisions. After taking into account the sub-nucleon structure effect, our numerical result can qualitatively describe the relative flow fluctuations ( ${v_2\{4\}/v_2\{2\}}$ , $F({v_2})$ ) measured by the ALICE Collaboration at the LHC. We further investigate the effects of shear viscosity, sub-nucleon structure, and initial condition model on the flow angle and flow magnitude decorrelations ( ${A_2^f}$ , ${M_2^f}$ ) using the four-particle correlation method. We find that the flow decorrelation effect is typically stronger in central collisions than in peripheral collisions. The flow angle decorrelation is found to be insensitive to the shear viscosity and sub-nucleon structure, whereas the flow magnitude decorrelation shows quite different behaviors when using the TRENTO and AMPT initial condition models. Our study sheds light on the anisotropic flow, transport properties, and initial structure of the QGP created in high-energy nuclear collisions.

Germany

Jie Zhu

Canada

Xiang-Yu Wu

Guang-You Qin

Anisotropic flow, flow fluctuation, and flow decorrelation in relativistic heavy-ion collisions: the roles of sub-nucleon structure and shear viscosity * Supported in part by the Natural Science Foundation of China (12225503, 11890710, 11890711, 11935007). Zhu Jie is supported in part by the China Scholarship Council (202306770009). Wu Xiang-Yu is supported in part by the National Science Foundation within the framework of the JETSCAPE collaboration (OAC-2004571) and in part by the Natural Sciences and Engineering Research Council of Canada. Some of the calculations were performed in the Nuclear Science Computing Center at Central China Normal University (NSC$^{3}$), Wuhan, Hubei, China.

A plasmon, a collective mode of electronic excitation in solid-state detectors, provides a novel way to detect light dark matter (DM). In this work, we present the conditions of DM to produce a plasmon resonance, requiring relativistic velocities for light DM, and generalize the collective excitation framework to account for relativistic DM. As a demonstration, we consider the cosmic ray boosted DM and find that the plasmon resonance can be significantly enhanced in the scenario with a light mediator. Utilizing the first data from the SENSEI experiment with the skipper CCDs at SNOLAB, we obtain a new strong limit on the sub-MeV DM-electron scattering cross section.

Zheng-Liang Liang

Liangliang Su

Plasmon-Enhanced Direct-Detection Method for Boosted Sub-MeV Dark Matter

Neutron stars provide ideal astrophysical laboratories for probing new physics beyond the Standard Model. If axions exist, then photons can develop linear polarization during photon-axion conversion in the magnetic field of a neutron star. We find that the plasma in the neutron star magnetosphere could dramatically enhance the polarization through the resonant conversion effect. With the polarization measurements from PSR <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="normal">B</mi><mn>0656</mn><mo>+</mo><mn>14</mn></mrow></math>, 4U <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>0142</mn><mo>+</mo><mn>61</mn></mrow></math>, and the benchmark polarization measurement in the midinfrared band, we demonstrate that optical and infrared polarization from neutron stars can provide strong constraints on the axion-photon coupling over a broad axion mass range <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>10</mn><mrow><mo>−</mo><mn>11</mn></mrow></msup><mo>≲</mo><msub><mi>m</mi><mi>a</mi></msub><mo>≲</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>3</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi></math>.

Ningqiang Song

Polarization signals from axion-photon resonant conversion in a neutron star magnetosphere

We investigate the Klein-Gordon (KG) oscillators in a global monopole (GM) spacetime in Eddington-inspired Born-Infeld (EiBI) gravity and a Wu-Yang magnetic monopole (WYMM). We discuss the gravitational effects in the presence of Ricci scalar curvature <math altimg='si1.svg'><mi>R</mi><mo linebreak='goodbreak' linebreakstyle='after'>=</mo><msubsup><mrow><mi>R</mi></mrow><mrow><mi>&#965;</mi></mrow><mrow><mi>&#965;</mi></mrow></msubsup></math>. It is observed that the presence of the Ricci scalar curvature, effectively and manifestly, introduces a force field that makes the corresponding quantum mechanical repulsive core more repulsive. Similar effect is also observed for the EiBI-gravitational field. We reiterate and report that the corresponding bosonic KG-oscillator quantum mechanical system admits a solution in the form of confluent Heun functions, the truncation of which into a physically admissible polynomial is shown to be associated with some parametric correlations/conditions. The use of such conditions/correlations is mandatory and yields a set of allowed/restricted quantum mechanical orbital <italic>&#8467;</italic>-excitations, for all radial quantum numbers <math altimg='si2.svg'><msub><mrow><mi>n</mi></mrow><mrow><mi>r</mi></mrow></msub><mo>&#8805;</mo><mn>0</mn></math>. Our procedure is shown to be quite handy, in the sense that it allows one to retrieve results for KG-oscillators in GM-spacetime in different EiBI-gravity and Ricci scalar curvature settings.

Türkiye

Omar Mustafa

KG-oscillators in Eddington-inspired Born-Infeld gravity: Wu-Yang magnetic monopole and Ricci scalar curvature effects