Wed·Jan 3, 2024Wednesday·January 3, 2024

1. 01*

   Thermal leptogenesis in the presence of helical hypermagnetic fields

   Sahar Safari🇮🇷 · Mehran Dehpour🇨🇿 · Saeed Abbaslu🇮🇷

   One of the major challenges in particle physics and cosmology is understanding why there is an asymmetry between matter and antimatter in the Universe. One possible explanation for this phenomenon is thermal leptogenesis, which involves the addition of at least two right-handed neutrinos (RHNs) to the standard model. Another possible explanation is baryogenesis through the hypermagnetic fields which involves the ${\mathrm{U}}_Y(1)$ anomaly and helical hypermagnetic fields in the early Universe. In this paper, after reviewing the thermal leptogenesis and baryogenesis through the ${\mathrm{U}}_Y(1)$ anomaly, we investigate the simplest model that combines these two scenarios and explore the parameter space for optimal results. Our results show that the combined scenario permits a specific region of parameter space that is not covered by either one separately. In fact, the minimum required mass scale of the RHN and strength of initial hypermagnetic helicity are reduced by one order of magnitude in our model. Moreover, we find that in the combined scenario, leptogenesis and baryogenesis through the ${\mathrm{U}}_Y(1)$ anomaly can either amplify or reduce the effect of each other, i.e., the generated asymmetry, depending on the sign of the helical hypermagnetic fields. Finally, we show the surprising result that a drastic amplification can occur even when the initial abundance of RHN is its equilibrium value for leptogenesis.

   hep-phastro-ph.COPhys.Dark Univ.(2024)·0 citations
2. 02*

   Femtoscopy with Lévy sources from SPS through RHIC to LHC

   Máté Csanád🇭🇺 · Dániel Kincses🇭🇺

   Femtoscopy is a unique tool to investigate the space-time geometry of the matter created in ultra-relativistic collisions. If the probability density distribution of hadron emission is parametrized, then the dependence of its parameters on particle momentum, collision energy, and collision geometry can be given. In recent years, several measurements came to light that indicated the adequacy of assuming a Lévy-stable shape for the mentioned distribution. In parallel, several new phenomenological developments appeared, aiding the interpretation of the experimental results or providing tools for the measurements. In this paper, we discuss important aspects of femtoscopy with Lévy sources in light of some of these advances, including phenomenological and experimental ones.

   hep-phnucl-thUniverse(2024)·23 citations
3. 03*

   Mixed QCD-EW corrections to $W$-pair production at electron-positron colliders

   Zhe Li🇨🇳 · Ren-You Zhang🇨🇳 · Shu-Xiang Li🇨🇳 · Xiao-Feng Wang🇨🇳 · Wen-Jie He🇨🇳 · Liang Han🇨🇳 · Yi Jiang🇨🇳 · Qing-hai Wang🇸🇬

   The discrepancy between the CDF measurement and the Standard Model theoretical prediction for the $W$-boson mass underscores the importance of conducting high-precision studies on the $W$ boson, which is one of the predominant objectives of proposed future $e^{+}{e}^{-}$ colliders. We investigate in detail the production of $W$-boson pairs at $e^{+}{e}^{-}$ colliders, and compute the next-to-next-to-leading order mixed QCD-EW corrections to both the integrated cross section and various kinematic distributions. By employing the method of differential equations, we analytically calculate the two-loop master integrals for the mixed QCD-EW virtual corrections to $e^{+}{e}^{-}\to W^{+}{W}^{-}$. Utilizing the Magnus transformation, we derive a set of canonical master integrals for each integral family. This canonical basis satisfies a system of differential equations in which the dependence on the dimensional regulator is linearly factorized from the kinematics. We then express all these canonical master integrals as Taylor series in $ϵ$ up to ${ϵ}^4$, with coefficients articulated in terms of Goncharov polylogarithms up to weight four. Upon applying our analytic expressions of these master integrals to the phenomenological analysis of $W$-pair production, we observe that the $\mathcal{O}(\alpha {\alpha }_s)$ corrections are significantly impactful in the $\alpha (0)$ scheme, particularly in certain phase-space regions. However, these mixed QCD-EW corrections can be heavily suppressed by adopting the $G_{\mu }$ scheme.

   hep-phJHEP(2024)·4 citations
4. 04*

   Deep learning bulk spacetime from boundary optical conductivity

   Byoungjoon Ahn🇰🇷 · Hyun-Sik Jeong🇪🇸 · Keun-Young Kim🇰🇷 · Kwan Yun🇰🇷

   We employ a deep learning method to deduce the \textit{bulk} spacetime from \textit{boundary} optical conductivity. We apply the neural ordinary differential equation technique, tailored for continuous functions such as the metric, to the typical class of holographic condensed matter models featuring broken translations: linear-axion models. We successfully extract the bulk metric from the boundary holographic optical conductivity. Furthermore, as an example for real material, we use experimental optical conductivity of ${\text{UPd}}_2{\text{Al}}_3$, a representative of heavy fermion metals in strongly correlated electron systems, and construct the corresponding bulk metric. To our knowledge, our work is the first illustration of deep learning bulk spacetime from \textit{boundary} holographic or experimental conductivity data.

   ↳ hep-thcond-mat.dis-nngr-qchep-phJHEP(2024)·36 citations
5. 05*

   Optimization of performance of the KM2A full array using the Crab Nebula

   LHAASO collaboration

   The full array of the Large High Altitude Air Shower Observatory (LHAASO) has been in operation since July 2021. For its kilometer-square array (KM2A), we have optimized the selection criteria for very high and ultra-high energy $\gamma$-rays, using the data collected from August 2021 to August 2022, resulting in an improvement on significance of about 15$\%$ compared with previous cuts. With the implementation of these new selection criteria, the angular resolution is also significantly improved by approximately 10$\%$ at tens of TeV. Other aspects of the full KM2A array performance, such as the pointing error are also calibrated using the Crab Nebula. The resulting energy spectrum of the Crab Nebula in the energy range of 10-1000 TeV can be well fitted by a log-parabola model, which is consistent with the previous results from LHAASO and other experiments.

   ↳ astro-ph.IMhep-phCPC(2024)·16 citations
6. 06*

   Bose-Einstein Condensate and Liquid Helium He${}^4$: Implications of GUP and Modified Gravity Correspondence

   Aneta Wojnar🇪🇸

   Utilizing the recently established connection between Palatini-like gravity and linear Generalized Uncertainty Principle (GUP) models, we have formulated an approach that facilitates the examination of Bose gases. Our primary focus is on the ideal Bose-Einstein condensate and liquid helium, chosen as illustrative examples to underscore the feasibility of tabletop experiments in assessing gravity models. The non-interacting Bose-Einstein condensate imposes constraints on linear GUP and Palatini $f(R)$ gravity (Eddington-inspired Born-Infeld gravity) within the ranges of $-10^{12}\lesssim \sigma \lesssim 3\times 10^{24}\text{ s}/\text{kg m}$ and $-10^{-1}\lesssim \bar{\beta }\lesssim 10^{11}{\text{ m}}^2$ ($-4\times 10^{-1}\lesssim ϵ\lesssim 4\times 10^{11}{\text{ m}}^2$), respectively. In contrast, the properties of liquid helium suggest more realistic bounds, specifically $-10^{23}\lesssim \sigma \lesssim 10^{23}\text{ s}/\text{kg m}$ and $-10^9\lesssim \bar{\beta }\lesssim 10^9{\text{ m}}^2$. Additionally, we argue that the newly developed method employing Earth seismic waves provides improved constraints for quantum and modified gravity by approximately one order of magnitude.

   ↳ gr-qchep-phPRD(2024)·5 citations
7. 07*

   Can Bell inequalities be tested via scattering cross-section at colliders ?

   Song Li🇨🇳 · Wei Shen🇨🇳 · Jin Min Yang🇨🇳

   In current studies for testing Bell inequalities at colliders, the reconstruction of spin correlations from scattering cross-sections relies on the bilinear form of the spin correlations, but not all local hidden variable models (LHVMs) have such a property. To demonstrate that a general LHVM cannot be rule out via scattering cross-section data, we propose a specific LHVM, which can exactly duplicate the same scattering cross-section for particle production and decay as the standard quantum theory, making it indistinguishable at colliders in principle. Despite of this, we find that reconstructing spin correlations through scattering cross-sections can still exclude a broad class of LHVMs, e.g., those models employing classical spin correlations as a surrogate for quantum spin correlations.

   ↳ hep-thhep-phquant-phEPJC(2024)·29 citations
8. 08*

   The reaction $\pi N\to \omega N$ in a dynamical coupled-channel approach

   Yu-Fei Wang🇩🇪

   This talk is on a refined investigation on light flavor meson-baryon scatterings, using a dynamical coupled-channel approach, i.e. the Jülich-Bonn model. The previous channel space of $\pi N$, $\pi \Delta$, $\sigma N$, $\rho N$, $\eta N$, $K\Lambda$ and $K\Sigma$ is extended by adding the $\omega N$ final state. The spectra of $N^{\ast }$ and $\Delta$ resonances are extracted, based on the result of a global fit to a worldwide collection of data, in the energy region from the $\pi N$ threshold to center-of-mass energy $z=2.3$ GeV (approximately $300$ parameters against $9000$ data points). A negative value of the $\omega N$ elastic spin-averaged scattering length has been extracted.

   ↳ nucl-thhep-phnucl-exphysics.comp-phEPJ Web Conf.(2024)·3 citations
9. 09*

   On the nature of the $N^{\ast }$ and $\Delta$ resonances via coupled-channel dynamics

   Yu-Fei Wang🇩🇪

   This talk focuses on a recent work aiming at determining the composition of certain $N^{\ast }$ and $\Delta$ resonances, i.e. whether they are compact states formed directly by quarks and gluons, or composite generated from the meson-baryon interaction. The information of the resonance poles is provided by a comprehensive coupled-channel approach, the Jülich-Bonn model. Thirteen states that are significant in this approach are studied. Two criteria for each state are adopted in this paper, the comparison thereof roughly indicates the model uncertainties. It is found that the conclusions for eight resonances are relatively certain: $N(1535){\frac{1}{2}}^{-}$, $N(1440){\frac{1}{2}}^{+}$, $N(1710){\frac{1}{2}}^{+}$, and $N(1520){\frac{3}{2}}^{-}$ tend to be composite; whereas $N(1650){\frac{1}{2}}^{-}$, $N(1900){\frac{3}{2}}^{+}$, $N(1680){\frac{5}{2}}^{+}$, and $\Delta (1600){\frac{3}{2}}^{+}$ tend to be compact.

   ↳ nucl-thhep-phEPJ Web Conf.(2024)·1 citation
10. 10*

    Charm Fluctuations and Deconfinement

    Sipaz Sharma🇩🇪

    We establish that the charmed hadrons start dissociating at the chiral crossover temperature, $T_{pc}$, leading to the appearance of charm degrees freedom carrying fractional baryon number. Our method is based on analyzing the second and fourth-order cumulants of charm ($C$) fluctuations, and their correlations with baryon number ($B$), electric charge ($Q$) and strangeness ($S$) fluctuations. The first-time calculation of the $QC$ correlations on the high statistics datasets of the HotQCD Collaboration enables us to disentangle the contributions from different electrically-charged charm subsectors in the hadronic phase. In particular, we see an enhancement over the PDG expectation in the fractional contribution of the $|Q|=2$ charm subsector to the total charm partial pressure for $T<T_{pc}$; this enhancement is in agreement with the Quark Model extended Hadron Resonance Gas (QM-HRG) model calculations. Furthermore, the agreement of QM-HRG calculations with the projections onto charmed baryonic and mesonic correlations in different charm subsectors indicates the existence of not-yet-discovered charmed hadrons in all charm subsectors below $T_{pc}$. We aim at determining the relevant degrees of freedom in temperature range $T_{pc}<T<340\text{ MeV}$ by assuming the existence of a non-interacting gas of charmed quasi-particles composed of meson, baryon and quark-like excitations above $T_{pc}$. Our data suggest that the particles with quantum numbers consistent with quarks start appearing at $T_{pc}$.

    ↳ hep-lathep-phPoS(2024)·6 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.