Thu·Sep 19, 2024Thursday·September 19, 2024

1. 01*

   Pion Boer-Mulders function using a contact interaction

   Dan-Dan Cheng🇨🇳 · Zhu-Fang Cui🇨🇳 · Minghui Ding🇩🇪 · Craig D. Roberts🇨🇳 · Sebastian M. Schmidt🇩🇪

   A symmetry preserving treatment of a vector $\otimes$ vector contact interaction (SCI) is used as the basis for calculations of the two pion transverse momentum dependent parton distribution functions (TMDs); namely, that for unpolarised valence degrees-of-freedom and the analogous Boer-Mulders (BM) function. Amongst other things, the analysis enables the following themes to be addressed: the quark current mass dependence of pion TMDs; the impact of the gauge link model on the positivity constraint that bounds the BM function relative to the unpolarised TMD; the equivalence of direct diagrammatic and light-front wave function TMD calculations; and the size of the BM shift. Interpreted astutely, these SCI results enable one to draw insightful pictures of pion TMDs.

   hep-phhep-exhep-latnucl-ex+1EPJC(2025)·11 citations
2. 02*

   Sea-quark dynamics in decuplet (${\frac{3}{2}}^{+}$) $\to$ octet (${\frac{1}{2}}^{+}$) transition quadrupole moment

   Preeti Bhall🇮🇳 · Alka Upadhyay🇮🇳

   We investigated the electromagnetic quadrupole transition of baryon decuplet ($J^P={\frac{3}{2}}^{+}$) to octet ($J^P={\frac{1}{2}}^{+}$) using the statistical framework together with the principle of detailed balance. The statistical approach assumed the expansion of hadrons in terms of various quark-gluon Fock states. By specifying the appropriate multiplicity in spin, color $\&$ flavor space, the relative probabilities of strange and non-strange quark-gluon Fock state are calculated. These probabilities further accumulated in the form of statistical parameters, highlighting the importance of sea quarks and gluons in the electromagnetic transition. Our calculations includes the individual contribution of valence and sea (scalar, vector and tensor ) to the transition moment of baryons. The effect of flavor SU(3) symmetry and its breaking in both valence and sea quarks is studied by incorporating the strange quark mass. The strangeness in the sea is constrained by a suppression factor $(1-C_l{)}^{n-1}$, which depends upon the free energy of gluons. The computed results get affected upto 60 $\%$ and exhibit the dominance of octet sea. The present work has been compared with updated experimental data and various theoretical predictions. The results obtained may offer important insights for future experimental studies.

   hep-phEPJC(2025)·1 citation
3. 03*

   On Precision of the Leptonic Mixing Angle ${\theta }_{23}$ and its Implications for the Flavor Models

   Son Cao🇻🇳 · P. T. Quyen🇻🇳 · N. T. Hong Van🇻🇳 · Ankur Nath🇮🇳 · T. V. Ngoc🇯🇵

   Among three leptonic mixing angles, ${\theta }_{23}$ angle, which characterizes the fractional contribution of two flavor eigenstates ${\nu }_{\mu }$ and ${\nu }_{\tau }$ to the third mass eigenstate ${\nu }_3$, is known to be the largest but the least precisely measured. The work investigates possible reach of ${\theta }_{23}$ precision with two upcoming gigantic accelerator-based long-baseline neutrino experiments, namely Hyper-Kamiokande and DUNE experiments as well as a possible joint analyses of future neutrino facilities. Our simulation yields that each experiment will definitely establish the octant of ${\theta }_{23}$ angle for all values within 1$\sigma$ parameter interval, while considering the current limitation. However, if the actual value is $0.48\le {\sin }^2{\theta }_{23}\le 0.54$, it becomes challenging for these two experiments to reject the maximal (${\theta }_{23}=\pi /4$) hypothesis and conclude its octant. This octant-blind region can be further explored with the proposed facilities ESSnuSB and a neutrino factory. Accurate determination of the mixing angle ${\theta }_{23}$, as well as the accuracy of ${\delta }_{CP}$, is crucial for examining a certain category of discrete non-Abelian leptonic flavor models. Specifically if CP is conserved in leptonic sector, the combined analysis of Hyper-K and DUNE will rule out the majority of these models. However, if the CP is maximally violated, higher precision of ${\delta }_{CP}$ is necessary for testing these flavor models.

   hep-phhep-exPRD(2025)·1 citation
4. 04*

   Spin resolved momentum spectra for vacuum pair production via a generalized two level model

   Orkash Amat🇨🇳 · Hong-Hao Fan🇨🇳 · Suo Tang🇨🇳 · Yong-Feng Huang🇨🇳 · Bai-Song Xie🇨🇳

   We have formulated a generalized two level model for studying the pair production in multidimensional time-dependent electric fields. It can provide momentum spectra with fully spin resolved components for all possible combined spin states of the particle and anti-particle simultaneously. Moreover, we have also investigated the validity of the two level model for fermions (scalar particles) by comparing the results with those by equal-time Dirac-Heisenberg-Wigner (Feshbach-Villars-Heisenberg-Wigner) formalism in different regimes of pair creation, i.e., multiphoton and tunneling dominated mechanisms. It is found that the results are consistent with each other, indicating the good approximation of the two level model. In particular, in terms of the two level model, we found that the contribution of the particle momentum spectra is the greatest when the spin states of the particle and anti-particle are parallel with $S=1$. It is believed that by this two level model one can extend researches on pair production for more different background fields, such as a slowly varying spatial-temporal one. Many other interesting phenomena may also be revealed, including the spin-resolved vortex structure that is contained in the phase feature of the distribution function of the created pairs.

   hep-phquant-phPRD(2025)·12 citations
5. 05*

   Effective masses and magnetic moments of charmed baryons in asymmetric hot strange hadronic matter

   Suneel Dutt🇮🇳 · Arvind Kumar🇮🇳 · Harleen Dahiya🇮🇳

   In the present work, we have studied the masses and magnetic moments of spin$-{\frac{1}{2}}^{+}$ and spin$-{\frac{3}{2}}^{+}$ singly and doubly charmed baryons in the strange hadronic medium at finite temperature using the chiral SU(3) quark mean field model. The properties of baryons within the framework of chiral SU(3) mean field model are defined in terms of constituent quark masses and energies, which are modified through the exchange of scalar fields $\sigma$, $\zeta$ and $\delta$ and the vector fields $\omega$, $\rho$ and $\varphi$. The scalar-isovector field, $\delta$ and the vector-isovector field, $\rho$ contribute when medium has finite isospin asymmetry. We have calculated the effective masses of constituent quarks and charmed baryons in the nuclear and strange matter within the chiral SU(3) quark mean field model and have used these as the input in SU(4) constituent chiral quark model to compute the effective magnetic moments of these baryons. Considering the configuration mixing, the contributions of valence quarks, quark sea and orbital angular momentum of quark sea have been considered explicitly to calculate the in-medium magnetic moments.

   hep-phPRD(2024)·6 citations
6. 06*

   Fully charmed tetraquark production at the LHC experiments

   Ilia Belov🇮🇹 · Alessandro Giachino🇪🇸 · Elena Santopinto🇮🇹

   We develop the formalism for production of a fully heavy tetraquark and apply it to the calculation of $pp\to T_{4c}+X$ cross-sections. We demonstrate that the production cross-section of a fully heavy tetraquark, even if it is a diquark-antidiquark cluster, can be obtained in the meson-like basis, for which the spin-color projection technique is well established. Prompted by the recent LHCb, ATLAS and CMS data, we perform a pQCD calculation of $\mathcal{O}({\alpha }_s^5)$ short-distance factors in the dominant channel of gluon fusion, and match these to the four-body $T_{4c}$ wave functions in order to obtain the unpolarized $T_{4c}(0^{++},1^{+-},2^{++})$ cross-sections. The novelty in comparison with the recently published article~\cite{Feng:2023agq} lies in the fact that we predict the absolute values as well as the $d\sigma /d{p}_T$ spectra in the kinematic ranges accessible at the ongoing LHC experiments. From the comparison with the signal yield at LHCb we derive the constraints on the $\Phi \cdot \text{Br}(J/\psi J/\psi )$ (reduced wave function times branching) product for the $T_{4c}$ candidates for $X(6900)$ and observe that $X(6900)$ is compatible with a $2^{++}(2S)$ state.

   hep-phhep-exJHEP(2025)·15 citations
7. 07*

   Unveiling the Secrets of New Physics Through Top Quark Tagging

   Rameswar Sahu🇮🇳 · Saiyad Ashanujjaman🇨🇳 · Kirtiman Ghosh🇮🇳

   The ubiquity of top-rich final states in the context of beyond the Standard Model (BSM) searches has led to their status as extensively studied signatures at the LHC. Over the past decade, numerous endeavours have been undertaken in the literature to develop methods for efficiently distinguishing boosted top quark jets from QCD jets. Although cut-based strategies for boosted top tagging, which rely on substructure information from fat jets resulting from the hadronic decay of boosted top quarks, were introduced in the literature as early as 2008, recent years have witnessed a surge in the utilization of machine learning-based approaches for the classification of top-jets from QCD jets. The review focuses on the present status of boosted top tagging and its application for BSM searchers.

   hep-phEur.Phys.J.ST(2024)·6 citations
8. 08*

   Far-from-equilibrium attractors with Full Relativistic Boltzmann approach in 3+1 D: moments of distribution function and anisotropic flows $v_n$

   Vincenzo Nugara (1 and 2)🇮🇹 · Vincenzo Greco (1 and 2)🇮🇹 · Salvatore Plumari (1 and 2) ((1) Department of Physics and Astronomy, University of Catania, Catania, (2) INFN-Laboratori Nazionali del Sud, Catania, Italy)🇮🇹

   We employ the Full Relativistic Boltzmann Transport approach for a conformal system in 3+1D to study the universal behaviour in moments of the distribution function and anisotropic flows. We investigate different transverse system sizes $R$ and interaction strength $\eta /s$ and identify universality classes based upon the interplay between $R$ and the mean free path; we show that each of this classes can be identified by a particular value of the opacity $\hat{\gamma }$, which has been previously introduced in literature. Our results highlight that, at early times, the inverse Reynolds number and momentum moments of the distribution function display universal behaviour, converging to a 1D attractor driven by longitudinal expansion. This indicates that systems of different sizes and interaction strengths tend to approach equilibrium in a similar manner. We provide a detailed analysis of how the onset of transverse flow affects these moments at later times. Moreover, we investigate the system size and $\eta /s$ dependence for the harmonic flows $v_2$, $v_3$, $v_4$ and their response functions, along with the impact of the $\eta /s$ and the system transverse size on the dissipation of initial azimuthal correlations in momentum space. Finally, we introduce the normalised elliptic flow $v_2/v_{2,eq}$, showing the emergence of attractor behaviour in the regime of large opacity. These results offer new insights into how different systems evolve towards equilibrium and the role that system size and interaction play in this process.

   hep-phnucl-thEPJC(2025)·19 citations
9. 09*

   Leading-colour-based unweighted event generation for multi-parton tree-level processes

   Rikkert Frederix🇸🇪 · Timea Vitos🇸🇪

   In this work, we revisit unweighted event generation for multi-parton tree-level processes in massless QCD. We introduce a two-step approach, in which initially unweighted events are generated at leading-colour (LC) accuracy, followed by a reweighting of these events to full-colour (FC) accuracy and applying an additional unweighting cycle. This method leverages the simple structure of LC integrands, enabling optimized phase-space parameterisations and resulting in high primary unweighting efficiencies, ranging from the percent level for $2\to 4$ processes to the per-mille level for $2\to 7$ processes. Given that the LC-accurate matrix elements closely approximate the FC-accurate ones, the secondary unweighting efficiencies exceed 50%. Our results suggest that this two-step approach offers an efficient alternative to direct event generation at FC accuracy.

   hep-phhep-exJHEP(2024)·7 citations
10. 10*

    Probing the cosmic sterile-neutrino background with IceCube

    Bhavesh Chauhan🇮🇳 · Priyank Parashari🇺🇸

    In this paper, we take a close look at the interaction between the TeV--PeV energy astrophysical neutrinos and a hypothetical cosmic sterile-neutrino background. These interactions yield absorption features, also called ``dips", in the astrophysical neutrino spectrum, which are studied using the deposited energy distribution of high-energy starting events (HESE) in the IceCube detector. We improve upon the previous analysis by including the effects of regeneration and a realistic source distribution on the propagation of astrophysical neutrinos. We use the latest 7.5-year HESE dataset and include the observation of Glashow resonance in our analysis. We evaluate the impact of these dips on the inferred spectral index and overall normalization of the astrophysical neutrinos. We find a mild preference for dips in the 300--800 TeV range, and the best-fit parameters for the mass of sterile-neutrino and the mediator are 0.5 eV and 23 MeV, respectively. We find that the inclusion of these absorption features lowers the spectral index of astrophysical neutrinos to $2.60_{-0.16}^{+0.19}$. We show qualitatively that the lower spectral index from HESE sample can reduce the disagreement with the Northern Tracks sample. We also forecast the event spectrum for IceCube-Gen2 for the two different fits.

    hep-phPRD(2025)·4 citations
11. 11*

    Phase Separation Unlocks Resonant Leptogenesis

    Jason Arakawa🇺🇸 · Philip Lu🇰🇷 · Volodymyr Takhistov🇯🇵

    Distinct behavior of decaying particles in true and false vacua of the theory can lead to enhanced generation of baryon asymmetry, a scenario we call \textit{phase separation baryogenesis}. We demonstrate that for leptogenesis this naturally allows for right handed neutrinos to generate resonantly-enhanced lepton asymmetry without fine-tuning of their masses as in typical theories. Our mechanism allows for a variety of neutrino mass hierarchies and hence possible novel connections with observations. We present a concrete realization in a minimal model with a scalar field undergoing a phase transition.

    hep-phastro-ph.CO3 citations
12. 12*

    $\nu$-point energy correletors with FastEEC: small-$x$ physics from LHC jets

    Ankita Budhraja🇳🇱 · Hao Chen🇺🇸 · Wouter J. Waalewijn🇳🇱

    In recent years, energy correlators have emerged as a powerful tool for studying jet substructure, with promising applications such as probing the hadronization transition, analyzing the quark-gluon plasma, and improving the precision of top quark mass measurements. The projected $N$-point correlator measures correlations between $N$ final-state particles by tracking the largest separation between them, showing a scaling behavior related to DGLAP splitting functions. These correlators can be analytically continued in $N$, commonly referred to as $\nu$-correlators, allowing access to non-integer moments of the splitting functions. Of particular interest is the $\nu \to 0$ limit, where the small momentum fraction behavior of the splitting functions requires resummation. Originally, the computational complexity of evaluating $\nu$-correlators for $M$ particles scaled as $2^{2M}$, making it impractical for real-world analyses. However, by using recursion, we reduce this to $M{2}^M$, and through the FastEEC method of dynamically resolving subjets, $M$ is replaced by the number of subjets. This breakthrough enables, for the first time, the computation of $\nu$-correlators for LHC data. In practice, limiting the number of subjets to 16 is sufficient to achieve percent-level precision, which we validate using known integer-$\nu$ results and convergence tests for non-integer $\nu$. We have implemented this in an update to FastEEC and conducted an initial study of power-law scaling in the perturbative regime as a function of $\nu$, using CMS Open Data on jets. The results agree with DGLAP evolution, except at small $\nu$, where the anomalous dimension saturates to a value that matches the BFKL anomalous dimension.

    hep-phhep-exnucl-exnucl-thPLB(2025)·13 citations
13. 13*

    Towards an unbiased jet energy loss measurement

    Liliana Apolinário🇵🇹 · Lénea Luís🇵🇹 · José Guilherme Milhano🇵🇹 · João M. Silva🇵🇹

    The modifications imprinted on jets due to their interaction with Quark Gluon Plasma (QGP) are assessed by comparing samples of jets produced in nucleus-nucleus collisions and proton-proton collisions. The standard procedure ignores the effect of bin migration by comparing specific observables for jet populations at the same reconstructed jet transverse momentum ($p_T$). Since jet $p_T$ is itself modified by interaction with QGP, all such comparisons confound QGP induced modifications with changes that are simply a consequence of comparing jets that started out differently. The quantile matching procedure introduced by Brewer et al. directly estimates average fractional jet energy loss ($Q_{AA}$) and can thus mitigate this $p_T$ migration effect. In this work, we validate the procedure in more realistic scenarios that include medium response. We study the evolution of $Q_{AA}$ with jet radius, its sensitivity to minimum particle $p_T$ and medium response as implemented in two different models for jet evolution in heavy-ion collisions. Further, we use this procedure to establish that the difference between inclusive jet and $\gamma +$jet nuclear modification factors ($R_{AA}$) is dominated by differences in the spectral shape, leaving the colour charge of the jet initiating parton with a lesser role to play. Additionally, we compare $Q_{AA}$ to an experimentally proposed proxy for fractional jet energy loss, $S_{loss}$, showing that both quantities are similar, although the former provides a more clear physical interpretation. Finally, we show the size of the $p_T$ migration correction for four different substructure observables and how to reliably use the quantile procedure experimentally to improve existing measurements.

    hep-phhep-exnucl-thJHEP(2025)·7 citations
14. 14*

    Quark mass dependence of doubly heavy tetraquark binding

    W. G. Parrott🇨🇦 · B. Colquhoun🇬🇧 · A. Francis🇹🇼 · R. J. Hudspith🇩🇪 · R. Lewis🇨🇦 · K. Maltman🇨🇦

    The existence of bound doubly heavy tetraquark states was confirmed by the recent LHCb discovery of the doubly charmed $T_{cc}$, less than 1 MeV below the meson pair threshold. Others states with two heavy (bottom or charm) quarks could also be bound, perhaps more deeply. Here we discuss our previous work, and the improvements in our current, updated analysis of various heavy-heavy-light-light tetraquark candidates, including the light and heavy quark mass dependence of the binding.

    ↳ hep-lathep-phPoS(2025)·1 citation
15. 15*

    Quark saturation in the QCD phase diagram

    Marcus Bluhm🇫🇷 · Yuki Fujimoto🇺🇸 · Larry McLerran🇺🇸 · Marlene Nahrgang🇫🇷

    We determine the onset of Quarkyonic Matter corresponding to values of temperature and baryon chemical potential at which the quark phase space density becomes one. At zero temperature for baryon chemical potentials below the mass of the Lambda baryon, only nucleons contribute to the quark density. This is different at finite temperature, where all baryons, mesons and their resonances can be excited and thus add quarks to the phase space. The probability density to find a quark inside a hadron is determined using the Yukawa ansatz of the IdylliQ model of Quarkyonic Matter. We estimate separately the magnitude of the various contributions of nucleons, Delta baryons, pions as well as further hadrons and resonances. The uncertainty in the parametrization of the probability density to find a quark inside a nucleon is spanned by assuming that at zero temperature the transition density to Quarkyonic Matter is between one and three times that of nuclear matter. Various predictions for a possible critical point associated with the chiral phase transition are found close to a triple point at which the line of the deconfinement transition and the curve associated with the transition to Quarkyonic Matter intersect. These considerations provide an estimate for the region in the QCD phase diagram where Quarkyonic Matter may be found.

    ↳ nucl-thhep-phPRC(2025)·15 citations
16. 16*

    From formation to evaporation: Induced gravitational wave probes of the primordial black hole reheating scenario

    Guillem Domènech🇩🇪 · Jan Tränkle🇩🇪

    We study the Primordial Black Hole (PBH) reheating scenario, where PBHs originate in a general cosmological background. In this scenario, ultralight PBHs with masses $M\lesssim 10^8$g temporarily dominate the Universe and reheat it via Hawking radiation before Big Bang Nucleosynthesis (BBN). We investigate whether the induced Gravitational Wave (GW) spectrum associated with PBH reheating contains information about the pre-PBH-dominated stage, namely the initial equation of state $w$ (after inflation). We first derive the transfer functions of curvature fluctuations for general $w$ with adiabatic and isocurvature initial conditions. We find that, in general, a stiffer equation of state enhances the induced GW amplitude as it allows for a longer PBH dominated phase compared to the radiation dominated case. We also find that the spectral slope of GWs induced by primordial curvature fluctuations is sensitive to $w$, while the spectral slope of GWs induced by PBH number density fluctuations is not. Lastly, we derive constraints of the initial PBH abundance as a function of $w$, using BBN and Cosmic Microwave Background (CMB) observations. A stiffer equation of state leads to stricter constraints on the initial energy density fraction, as induced GWs are enhanced. Interestingly, we find that such induced GW signals may enter the observational window of several future GW detectors, such as LISA and the Einstein Telescope. Our formulas, especially the curvature fluctuation transfer functions, are applicable to any early matter-dominated universe scenario.

    ↳ gr-qcastro-ph.COhep-phPRD(2025)·47 citations
17. 17*

    Dark dimension with (little) strings attached

    Ivano Basile🇩🇪 · Dieter Lust🇩🇪

    We motivate a relation between dark energy and the scale of new physics in weakly coupled string theory. This mixing between infrared and ultraviolet physics leads to a unique corner for real-world phenomenology: barring fine-tunings, we are naturally led to the ``dark dimension'' scenario, a single mesoscopic extra dimension of micron size with the standard model localized on D-branes. Our explicit top-down worldsheet derivation establishes it on a more solid grounding. Allowing some fine-tuning, such that the vacuum energy only arise at higher orders in string perturbation theory, the ``little string theory'' scenario with a very weakly coupled string is an alternative possibility. In this case, the string scale lies at the edge of detectability of particle accelerators.

    ↳ hep-thgr-qchep-phFortsch.Phys.(2025)·20 citations
18. 18*

    Quantum integration of decay rates at second order in perturbation theory

    Jorge J. Martínez de Lejarza🇪🇸 · David F. Rentería-Estrada🇪🇸 · Michele Grossi🇨🇭 · Germán Rodrigo🇪🇸

    We present the first quantum computation of a total decay rate in high-energy physics at second order in perturbative quantum field theory. This work underscores the confluence of two recent cutting-edge advances. On the one hand, the quantum integration algorithm Quantum Fourier Iterative Amplitude Estimation (QFIAE), which efficiently decomposes the target function into its Fourier series through a quantum neural network before quantumly integrating the corresponding Fourier components. On the other hand, causal unitary in the loop-tree duality (LTD), which exploits the causal properties of vacuum amplitudes in LTD to coherently generate all contributions with different numbers of final-state particles to a scattering or decay process, leading to singularity-free integrands that are well suited for Fourier decomposition. We test the performance of the quantum algorithm with benchmark decay rates in a quantum simulator and in quantum hardware, and find accurate theoretical predictions in both settings.

    ↳ quant-phhep-phQuantum Sci.Technol.(2025)·24 citations
19. 19*

    Comment on "Quantum-Mechanical Suppression of Gas Accretion by Primordial Black Holes"

    James M. Cline🇨🇦

    It was recently claimed (arXiv:2409.09081v1 [astro-ph.HE]) that accretion of ordinary matter on black holes of mass $(6\times 10^{14}-4\times 10^{19})$g would be inhibited by quantum mechanical effects, namely the de Broglie wavelength of the electron being larger than the Schwarzschild radius. However the conclusion is based on considering accretion of a single atom over the age of the Universe. There is no suppression of the accretion rate per atom on such black holes.

    ↳ astro-ph.HEgr-qchep-ph0 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.