We introduce building blocks for the cluster hadronization model in light of a new structure, focusing on cluster fission and cluster decay. We propose theoretically motivated matrix elements for cluster fission and decay as building blocks and study some first phenomenological implications at different energies. In particular we develop a set of observables which can be used to dissect the hadronization history and have constraining power on the individual building blocks. Our analysis will be completed by including colour reconnection in a follow-up work.

Germany

Stefan Gieseke

Stefan Kiebacher

Austria

Simon Plätzer

Jan Priedigkeit

Phenomenological constraints of the building blocks of the cluster hadronization model

The photon sphere defines the unstable circular orbit of photons in a black hole spacetime. Photons emitted by a source located inside the photon sphere can be gravitationally lensed by the black hole and have time delays when reaching the observer. These delays may lead to light echoes produced in the light curve if an accretion event in the vicinity of the horizon can be observed. In this work, we present fully analytical formulas with high accuracy to describe the change of the azimuthal angle and the travel time of those photons. By employing the analytical approaches, we find that the time delay between photons emitted from the interior of the photon sphere has a typical time scale of $$2(\pi - \phi _\textrm{S}) u_\textrm{m}$$ with $$\phi _\textrm{S}$$ and $$u_\textrm{m}$$ being respectively the azimuthal angle of the source and the impact parameter evaluated at the photon sphere, which can provide some clues on the future search for gravitational lensing signatures in the accretion inflow event.

China

Yuan-Xing Gao

Analytical description for light propagation with the source inside the black hole photon sphere

The Event Horizon Telescope (EHT) imaged black holes M87 $$^*$$ (angular diameter $$\theta _d = 42 \pm 3\,\upmu \text {as},$$ mass $$\sim 6.5 \times 10^9\,M_\odot )$$ and Sgr A $$^*$$ $$(\theta _d = 48.7 \pm 7\,\upmu \text {as},$$ shadow deviation $$\delta \approx -0.08^{+0.09}_{-0.09}$$ (VLTI), $$-0.04^{+0.09}_{-0.10})$$ (Keck). These observations enable tests of gravity in strong regimes. We propose a rotating non-commutative inspired Kiselev black hole (RNKBH), incorporating dark energy $$(\omega )$$ and non-commutative $$(\Theta )$$ parameters, extending Kerr solutions. Our analysis reveals that $$\omega = -2/3$$ allows larger $$\Theta $$ but requires $$a \ge 0.16M$$ to maintain horizons. Shadow calculations show significant deviations from Kerr predictions: for $$\Theta = 0.001-0.005M^2,$$ shadows shrink by 8-15% and distortion increases by 20-35% for rapidly spinning $$(a > 0.5M)$$ black holes. The $$\omega = -2/3$$ exhibits shadow squeezing near the cosmological horizon. We compute shadow observables and compare them with EHT data. For Sgr A $$^*$$ $$(50^\circ $$ inclination), the bounds are $$0.001497 \le \Theta \le 0.002868\,M^2$$ at $$a =0.9146$$ $$(\omega = -2/3)$$ . For M87 $$^*$$ $$(17^\circ )$$ , $$0 \le \Theta \le 0.004993 \,M^2$$ at $$a=0.0.6167$$ $$(\omega = -2/3)$$ . While EHT cannot yet distinguish RNKBH from Kerr BH, our results highlight its viability as an astrophysical candidate.

Fazlay Ahmed

India

Heena Ali

Qiang Wu

Tao Zhu

South Africa

Sushant Ghosh

Shadows of rotating non-commutative Kiselev black holes: constraints from EHT observations of M87* and Sgr A*

We compute various averages over bulk geometries of quantum states prepared by the Chern-Simons path integral, for any level <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>k</mi></math> and compact simple gauge group <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>G</mi></math>. We do so by carefully summing over all topologically distinct bulk geometries which have <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>n</mi></math> disjoint boundary tori and a decomposition into <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>space</mi><mo>×</mo><mi>time</mi></mrow></math> of fixed spatial topology. We find that to leading order in the complexity of the state, the typical state contains many types of multiparty entanglement, proving a conjecture of Balasubramanian et al. Combined with the fact that periodic link states are Greenberger–Horne–Zeilinger (GHZ)-like, this result implies that a generic fibered link state contains non-GHZ entanglement if and only if its link complement is hyperbolic. Additionally, we compute an averaged wave function which captures the leading order statistics of boundary observables in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>n</mi></math> torus Chern-Simons Hilbert space.

United States

Charlie Cummings

Entanglement in typical states of Chern-Simons theory

We discuss the dynamics of the quantum fluctuation around the nonlinear massive wave solution in the Higgs potential. In particular, we analyze the stability and instability of the mode function. Using the stability condition for Hill’s equation, we obtain the instability region of the mode function in the quantum fluctuation as the function of the parameters in the mode equation. We show that the two types of the instabilities of the system in the particle number can be understood by the Floquet’s exponents in the instability parameter region. The analysis will be useful to understand the dynamics of the quantum field theory around the nonlinear massive wave solution when the classical background slightly deviates from the constant background during the middle stage of the phase transition.

Taiwan

Yoshio Kitadono

Japan

Tomohiro Inagaki

Instability of quantum fluctuation around classical nonlinear massive wave solution in Higgs potential and particle creations

We investigate the volume and lifetime of the high-baryon-density matter created in heavy-ion collisions and estimate the optimal collision-energy range to realize the high-baryon-density region over a large space-time volume. We simulate central collisions of gold ions for the center-of-mass energy per nucleon pair <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>2.4</mn><mo>−</mo><mn>19.6</mn><mspace width="0.28em"></mspace><mi>GeV</mi></mrow></math> with a microscopic transport model JAM. We discover that the optimal range is around <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>3</mn><mo>−</mo><mn>5</mn><mspace width="0.28em"></mspace><mi>GeV</mi></mrow></math>, where a baryon density exceeding three times the normal nuclear density is realized with a substantially large space-time volume. Higher and lower energies are disfavored due to short lifetime and low density, respectively. We also point out that event-by-event fluctuations of the space-time density profile are large, indicating the importance of the event selection in the experimental analysis.

Hidetoshi Taya

Asanosuke Jinno

Masakiyo Kitazawa

Yasushi Nara

Optimal collision-energy range for realizing macroscopic high-baryon-density matter

We introduce a novel parametrization of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mi>π</mi><mi>π</mi><mo>ℓ</mo><mi>ν</mi></math> form factors relying on partial-wave decompositions and series expansions in suitable variables. We bound the expansion coefficients through unitarity and include left-hand cut contributions using established dispersive methods. The two-hadron line shapes are treated in a model-independent manner using Omnès functions, thus allowing for a data-driven determination of the expansion parameters. We study the underlying composition of the di-pion system in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mi>π</mi><mi>π</mi><mo>ℓ</mo><mi>ν</mi></math> decays through fits to differential spectra of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><msup><mo>ℓ</mo><mo>+</mo></msup><mi>ν</mi></math> measured by the Belle experiment. In contrast to previous works, we are able to study the full phase space and are not limited to certain kinematic regions. As a consequence, we extract branching fractions for the different partial waves of the di-pion system. We find <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><mo stretchy="false">(</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><msub><mo stretchy="false">)</mo><mi>S</mi></msub><msup><mo>ℓ</mo><mo>+</mo></msup><mi>ν</mi><mo stretchy="false">)</mo><mo>=</mo><msubsup><mn>2.2</mn><mrow><mo>−</mo><mn>1.0</mn></mrow><mrow><mo>+</mo><mn>1.4</mn></mrow></msubsup><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><mo stretchy="false">(</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><msub><mo stretchy="false">)</mo><mi>P</mi></msub><msup><mo>ℓ</mo><mo>+</mo></msup><mi>ν</mi><mo stretchy="false">)</mo><mo>=</mo><mspace linebreak="goodbreak"></mspace><msubsup><mn>19.6</mn><mrow><mo>−</mo><mn>2.7</mn></mrow><mrow><mo>+</mo><mn>2.8</mn></mrow></msubsup><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><mo stretchy="false">(</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><msub><mo stretchy="false">)</mo><mi>D</mi></msub><msup><mo>ℓ</mo><mo>+</mo></msup><mi>ν</mi><mo stretchy="false">)</mo><mo>=</mo><msubsup><mn>3.5</mn><mrow><mo>−</mo><mn>1.1</mn></mrow><mrow><mo>+</mo><mn>1.3</mn></mrow></msubsup><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup></math>. In addition, we derive predictions for the thus far unobserved <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>π</mi><mn>0</mn></msup><msup><mi>π</mi><mn>0</mn></msup><msup><mo>ℓ</mo><mo>+</mo></msup><mi>ν</mi></math> decay and obtain a sizable branching fraction of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>π</mi><mn>0</mn></msup><msup><mi>π</mi><mn>0</mn></msup><msup><mo>ℓ</mo><mo>+</mo></msup><mi>ν</mi><mo stretchy="false">)</mo><mo>=</mo><msubsup><mn>2.9</mn><mrow><mo>−</mo><mn>0.7</mn></mrow><mrow><mo>+</mo><mn>0.9</mn></mrow></msubsup><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup></math>.

Switzerland

Florian Herren

Bastian Kubis

Raynette van Tonder

Model-independent parametrization of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mi>π</mi><mi>π</mi><mo>ℓ</mo><mi>ν</mi></math> decays

The pseudorapidity density distributions of charged particles and the transverse-momentum spectra of identified particles in proton-proton (<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mi>p</mi></mrow></math>) collisions at the center-of-mass energies ranging from <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>200</mn></mrow></math> GeV to 13 TeV have been systematically studied using the newly released parton and cascade model paciae 4.0 based on pythia 8.3. The available experimental data are well reproduced across all analyzed aspects. This theoretical method can be easily extended to anywhere the experimental data for <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mi>p</mi></mrow></math> collisions are currently unavailable. Furthermore, since <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mi>p</mi></mrow></math> collisions serve as the baseline for heavy-ion collisions, our results can provide a valuable resource for both experimentalists and theorists.

Zhen Xie

An-Ke Lei

Hua Zheng

Wenchao Zhang

Dai-Mei Zhou

Zhi-Lei She

Yu-Liang Yan

Ben-Hao Sa

Pseudorapidity density distributions of charged particles and transverse-momentum spectra of identified particles in <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mi>p</mi></mrow></math> collisions in the PACIAE 4.0 model

We revisit birefringence effects associated with the evolution of the polarization of light as it propagates through axion dark matter or the background of a passing gravitational wave (GW). We demonstrate that this can be described by a unified formalism, highlighting a synergy between searches for axions and high-frequency GWs. We show that by exploiting this framework, the optical cavities used by the ALPS II experiment can potentially probe axion masses in the range <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>a</mi></msub><mo>∼</mo><mrow><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>9</mn></mrow></msup><mi>–</mi><mrow><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>6</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi></mrow></mrow></math>, offering competitive sensitivity with existing laboratory and astrophysical searches. Also building on this approach, we propose using these optical cavities to search for high-frequency GWs by measuring changes in the polarization of their circulating laser fields. This makes it a promising method for exploring, in the near future, GWs with frequencies above 100 MHz and strain sensitivities on the order of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>14</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>Hz</mi></mrow><mrow><mo>−</mo><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup></mrow></math>. Such sensitivity allows the exploration of currently unconstrained parameter space, complementing other high-frequency GW experiments. This work contributes to the growing community investigating novel approaches for high-frequency GW detection.

Spain

Camilo García-Cely

Luca Marsili

Andreas Ringwald

Aaron D. Spector

Polarimetric searches for axion dark matter and high-frequency gravitational waves using optical cavities

Atmospheric neutrino oscillations are important to the study of neutrino properties, including the neutrino mass ordering problem. A good capability to identify neutrinos’ flavor and neutrinos against antineutrinos is crucial in such measurements. In this paper, we present a machine-learning-based approach for identifying atmospheric neutrino events in a large homogeneous liquid scintillator detector. This method identifies features of photomultiplier tube waveforms that reflect event topologies and uses them as input to machine learning models. In addition, neutron-capture information is utilized to achieve neutrino vs antineutrino discrimination. Preliminary performances based on Monte Carlo simulations are presented, which demonstrate such a detector’s potential in future measurements of atmospheric neutrinos such as the one planned for the JUNO experiment.

Jiaxi Liu

Fanrui Zeng

Hongyue Duyang

Wanlei Guo

Xinhai He

Teng Li

Zhen Liu

Wuming Luo

Wing Yan Ma

Xiaohan Tan

Liangjian Wen

Zekun Yang

Yongpeng Zhang

Neutrino type identification for atmospheric neutrinos in a large homogeneous liquid scintillation detector