Fri·Jul 19, 2024Friday·July 19, 2024

1. 01*

   A Light QCD Axion with Hilltop Misalignment

   Raymond T. Co🇺🇸 · Tony Gherghetta🇺🇸 · Zhen Liu🇺🇸 · Kun-Feng Lyu🇺🇸

   We study the cosmological evolution of a light QCD axion and identify the parameter space to obtain the correct relic dark matter abundance. The axion potential is flattened at the origin, corresponding to the only minimum, while it is unsuppressed at $\pi$. These potential features arise by assuming a mirror sector with the strong CP phase $\bar{\theta }$ shifted by $\pi$ compared to the SM sector, which allows the mirror axion potential to be tuned against the usual QCD axion potential. Before the QCD phase transition, assuming the mirror sector is decoupled and much colder than the SM thermal bath, the mirror sector potential dominates, causing the axion to initially roll to a temporary minimum at $\pi$. However, after the QCD phase transition, the potential minimum changes, and the axion relaxes from the newly created "hilltop" near $\pi$ to the CP-conserving minimum at the origin. As the axion adiabatically tracks this shift in the potential minimum through the QCD phase transition, with non-adiabatic evolution near $\pi$ and 0, it alters the usual prediction of the dark matter abundance. Consequently, this "hilltop" misalignment mechanism opens new regions of axion parameter space, with the correct relic abundance while still solving the strong CP problem, that could be explored in future experiments.

   hep-phastro-ph.COhep-thJHEP(2024)·11 citations
2. 02*

   Transverse spin asymmetries and the electron Yukawa coupling at an FCC-ee

   Radja Boughezal🇺🇸 · Frank Petriello🇺🇸 · Kağan Şimşek🇺🇸

   We show that measurements of single transverse-spin asymmetries at an $e^{+}{e}^{-}$ collider can enhance the sensitivity to the electron Yukawa coupling, possibly enabling observation of the Standard Model value for this quantity. We demonstrate that the significance in both the $b\bar{b}$ and semi-leptonic $WW$ final states can be enhanced by factors of up to three compared to inclusive cross section determinations of this coupling for transversely-polarized electrons. If the positrons can be simultaneously longitudinally polarized, even at the level of 30\%, the significance can be enhanced by a factor of five or more. The method utilizes quantum interference between the Higgs signal and the continuum background and is also applicable in other $WW$ and $ZZ$ final states.

   hep-phhep-exPRD(2024)·8 citations
3. 03*

   ALARIC: A NLL accurate Parton Shower algorithm

   Florian Herren🇨🇭

   In this contribution, we summarize the key concepts behind the next-to-leading-logarithm accurate parton shower algorithm ALARIC. We discuss tests of the logarithmic accuracy and present comparisons to LEP data.

   hep-phPoS(2024)·0 citations
4. 04*

   Phenomenological Study of Lepton Flavor Violation in Z Boson Decays with Constrained MSSM Extended by Type-II Seesaw Model

   Vael Hajahmad🇹🇷 · Murhaf Alsayed Ali🇸🇾

   In this work, we study the lepton flavor violation (LFV) of Z boson decays in the framework of the constrained minimal supersymmetric standard model (CMSSM) extended by the type-II seesaw model. The branching ratios of $Z⟶l_i{l}_j$ decays are calculated in this model. Here, $l_i$ and $l_j$ are different flavor charged leptons. After fitting to the experimental mass limits of the neutrino and supersymmetric particles, we have found that the branching ratios for LFV decays of Z boson are in the order of $6\times {10}^{-10}$ for $e\mu$ channel and of $1\times {10}^{-9}$ for both $\tau \mu$ and $\tau e$ decay channels. Considering recent experimental constraints on $l_i\to l_j\gamma$ decays, the branching ratios for LFV decays of Z boson get an additional suppression of $10^{-8}$ for $e\mu$ channel and of $10^{-3}$ for both $\tau \mu$ and $\tau e$ decay channels. The branching ratios theoretical predictions are several orders below the recent experimental limits for both scenarios, which give a very low probability to observe the LFV decays of Z boson in the future experiments.

   hep-ph1 citation
5. 05*

   Quasi two-zero texture in Type-II seesaw at fixed points from modular $A_4$ symmetry

   Takaaki Nomura🇨🇳 · Hiroshi Okada🇨🇳

   We study a quasi two-zero neutrino texture based on a type-II seesaw model with modular $A_4$ symmetry to evade the cosmological bound on the sum of neutrino masses while keeping some predictability in the neutrino sector. Working on three fixed points for modulus, we discuss predictions of the model and show the allowed points satisfying the cosmological bound on neutrino mass from both CMB and CMB+BAO data.

   hep-phPTEP(2026)·6 citations
6. 06*

   Possible molecules of triple-heavy pentaquarks within the extended local hidden gauge formalism

   Zhong-Yu Wang🇨🇳 · Chu-Wen Xiao🇨🇳 · Zhi-Feng Sun🇨🇳 · Xiang Liu🇨🇳

   In this study, we explore the interactions between mesons and baryons in the open heavy sectors to identify potential triple-heavy molecular pentaquarks. We derive the meson-baryon interaction potentials using the vector meson exchange mechanism within the extended local hidden gauge formalism. The scattering amplitudes are computed by solving the coupled-channel Bethe-Salpeter equation, revealing several bound systems. By analyzing the poles of these amplitudes in the complex plane, we determine the masses and widths of these bound states. Additionally, we evaluate the couplings and compositeness of different channels within each bound system to assess their molecular characteristics. Our predictions include four ${\Omega }_{ccc}$-like states, four ${\Omega }_{bbb}$-like states, fourteen ${\Omega }_{bcc}$-like states, and ten ${\Omega }_{bbc}$-like states, which could be targets for future experimental investigations.

   hep-phPRD(2024)·6 citations
7. 07*

   The Stochastic Gravitational Wave Background from Primordial Gravitational Atoms

   Zhaofeng Kang🇨🇳 · Tianjun Li🇨🇳 · Weitao Ye🇨🇳

   We propose a scenario of primordial gravitational atoms (PGAs), which may exist in the current and past universe due to spinning primordial black holes (PBHs) and very light bosonic fields. In a monochromatic mass scenario with a sizable dimensionless spin, which may arise in a short matter dominated (MD) era, we analyze the resulting stochastic gravitational wave background (SGWB) signal. Its spectrum is approximately characterized by a rising $\propto f^3$ followed by a falling $\propto f^{-1}$ where $f$ is the frequency. Then, we investigate the constraints and prospects of such a SGWB, and find that PGAs with a core mass $M_{\mathrm{BH}}\sim \mathcal{O}(10)M_{\odot }$ and a cloud of light scalar with mass $\mu \sim \mathcal{O}(10^{-13})$ eV could yield constraints even stronger than those from bare PBHs. Future detectors such as LISA, Taiji and TianQin are able to explore PGAs over a narrow and elongated strap in the $(\mu ,M_{\mathrm{BH}})$ plane, spanning over 10 orders of magnitude for the maximum spin, $10^{-8}{M}_{\odot }\lesssim M_{\mathrm{BH}}\lesssim 10^4{M}_{\odot }$, $10^{-16}\mathrm{eV}\lesssim \mu \lesssim 10^{-3}\mathrm{eV}$. If the PGA is dressed with a vector cloud, the SGWB signal has a much better opportunity to be probed.

   hep-phastro-ph.COgr-qcJCAP(2024)·4 citations
8. 08*

   Angular momentum distribution for a quark dressed with a gluon: different decompositions

   Ravi Singh🇮🇳 · Sudeep Saha🇮🇳 · Asmita Mukherjee🇮🇳 · Nilmani Mathur🇮🇳

   We present a recent calculation of the quark and gluon contributions to the angular momentum of a composite spin -$1/2$ state in QCD. The state we consider is a quark dressed with a gluon, and we use the two-component framework in light-front Hamiltonian QCD. We compare the results from different decompositions available in the literature. We also present the angular momentum distributions.

   hep-phPoS(2025)·0 citations
9. 09*

   Four-Charm-Quark Matter from the CMS Collaboration as a Witness of the Development of High-Precision Hadron Spectroscopy

   Xiang Liu🇨🇳

   Recent CMS observations in the di-$J/\psi$ invariant mass spectrum reveal new structures at 6638 MeV ($X(6600)$)) and 7134 MeV, and confirm the $X(6900)$ at 6847 MeV. These findings provide crucial insights into four-charm-quark matter. The CMS Collaboration's result serves as a testament to the progress in exploring exotic hadronic matter.

   hep-phhep-exSci.Bull.(2024)·2 citations
10. 10*

    Identifying the two-pole structure of the $\Lambda (1405)$ using an SU(3) flavor filter

    Ying-Bo He🇨🇳 · Xiao-Hai Liu🇨🇳 · Li-Sheng Geng🇨🇳 · Feng-Kun Guo🇨🇳 · Ju-Jun Xie🇨🇳

    We propose a novel method to identify the two-pole structure of the $\Lambda (1405)$. The two poles owe their origin to different quark flavor irreducible representations in the meson-baryon coupled-channel interactions, thus they should be individually manifested in reactions that provide good flavor eigenstate sources. Hadronic decays of charmonia into $\bar{\Lambda }\Sigma \pi$ and $\bar{\Lambda }(1520)\Sigma \pi$ are such reactions, and the flavor octet and singlet poles can be approximately singled out in these two decay modes. This SU(3) flavor filter works even considering the flavor symmetry breaking. With the huge charmonium data sets collected, it is therefore promising to solve the long-standing $\Lambda (1405)$ puzzle employing the proposed flavor filter.

    hep-phhep-exnucl-thPRD(2026)·11 citations
11. 11*

    Constraining ${\lambda }_{B_s}$ by $B_s\to {\gamma }^{\ast }$ and $B_s\to \varphi$ form factors

    Mikhail A. Ivanov🇷🇺 · Dmitri Melikhov🇷🇺 · Silvano Simula🇮🇹

    We calculate the form factors $F_V(q^2,q^{\prime 2})$ and $F_{TV}(q^2,q^{\prime 2})$ describing the $B_s\to {\gamma }^{\ast }$ transition induced by the vector and tensor weak currents in a broad range of values of $q^2$ and $q^{\prime 2}$ far below the quark thresholds in both $q^2$ and $q^{\prime 2}$ channels. These form factors are calculated via the distribution amplitudes of the $B_s$-meson. We then interpolate the obtained results by a formula that contains pole at $q^{\prime 2}=M_{\varphi }^2$ and extract the residue which gives the $B_s\to \varphi$ transition form factors $V(q^2)$ and $T_1(q^2)$. In this way we obtain theoretical predictions for these form factors without invoking quark-hadron duality and QCD sum rules. Furthermore, we calculate the relationship between $V(0)$ and $T_1(0)$ and the parameter ${\lambda }_{B_s}(\mu )$, the inverse moment of the $B_s$-meson distribution amplitude. Using the available predictions for $V(0)$ and $T_1(0)$ coming from approaches not referring to the $B_s$-meson distribution amplitudes, we obtain the estimate ${\lambda }_{B_s}(\mu \simeq m_b)=(0.62\pm 0.10)$ GeV.

    hep-phPRD(2024)·0 citations
12. 12*

    $X_0(2900)$ and ${\chi }_{c0}(3930)$ in process $B^{+}\to D^{+}{D}^{-}{K}^{+}$

    Zuo-Ming Ding🇨🇳 · Qi Huang🇨🇳 · Jun He🇨🇳

    This study investigates the nature of the $X_0(2900)$ and ${\chi }_{c0}(3930)$ based on experimental results of the process $B^{+}$$\to$$D^{+}{D}^{-}{K}^{+}$. We focus on the S-wave $D^{\ast -}{K}^{\ast +}$ and $D_s^{+}{D}_s^{-}$ molecular states, which can be related to the $X_0(2900)$ and ${\chi }_{c0}(3930)$, respectively. Using effective Lagrangians, we construct the potential kernel of the $D^{\ast -}{K}^{\ast +}$$-$$D^{-}{K}^{+}$ and $D_s^{+}{D}_s^{-}$$-$$D^{+}{D}^{-}$ interactions with a one-boson-exchange model, and determine the scattering amplitudes and their poles through a quasipotential Bethe-Salpeter equation approach. By incorporating the potential kernel into the three-body decay process $B^{+}$$\to$$D^{+}{D}^{-}{K}^{+}$, we evaluate the $D^{-}{K}^{+}$ and $D^{+}{D}^{-}$ invariant mass spectra, as well as the Dalitz plot, with Monte Carlo simulation. A satisfactory fit to the $D^{-}{K}^{+}$ and $D^{+}{D}^{-}$ invariant mass spectra is achieved after introducing additional Breit-Wigner resonances, the $X_1(2900)$, $\psi (3770)$, and ${\chi }_{c2}(3930)$ states. Prominent signals of the $X_0(2900)$ and ${\chi }_{c0}(3930)$ states appear as peaks in the $D^{-}{K}^{+}$ and $D^{+}{D}^{-}$ invariant mass spectra near 2900 and 3930 MeV, respectively. Clear event concentration of the $X_0(2900)$ and ${\chi }_0(3930)$ states is evident as strips in the Dalitz plot. The results suggest that both $X_0(2900)$ and ${\chi }_{c0}(3930)$ can be interpreted as molecular states, with the inclusion of $X_1(2900)$ and ${\chi }_2(3930)$ necessary to describe structures in the regions near 2900 and 3930 MeV.

    hep-phEPJC(2024)·10 citations
13. 13*

    $B_s^0\to K^0\overline{K}{}^0$ beyond the Standard Model

    Yuval Grossman🇺🇸 · Yosef Nir🇮🇱 · Matthias Neubert🇺🇸 · Yogev Shpilman🇮🇱 · Yehonatan Viernik🇮🇱

    Within the Standard Model, the branching fraction of the rare decay $B_s\to K^0{\bar{K}}^0$ is related to other decay rates and CP asymmetries through the approximate $SU(3)$ flavor symmetry of the strong interactions and the heavy-quark limit. Three such relations were shown to be violated at a level of about $3\sigma$ each. By means of a systematic search for new-physics explanations of these puzzles, we find that possible solutions are highly fine-tuned and either excluded by other data or rather implausible. The tight correlation between $B_s\to K\bar{K}$ and $B\to \pi K$ decays, which is maintained even in the presence of flavor-specific new-physics operators, plays a central role in our analysis.

    hep-phJHEP(2025)·9 citations
14. 14*

    Hadronic Decays of a Higgs-mixed Scalar

    Patrick J. Blackstone🇺🇸 · Jaume Tarrús Castellà🇺🇸 · Emilie Passemar🇺🇸 · Jure Zupan🇺🇸

    One of the portals to new physics is a light scalar coupled to the Standard Model (SM) Higgs. In this paper we focus on hadronic decays of such a scalar in the regime where QCD dynamics is nonperturbative, resulting, e.g., in decays to pairs of pions or kaons, while also allowing for scalar couplings to the SM fermions to deviate from the Higgs-mixed light scalar limit. Representations of the corresponding form factors can be obtained using dispersive techniques, however, several sources of uncertainty affect the final results. We reexamine these decays, paying special attention to the quantification of uncertainties. For the light Higgs-mixed scalar scenario, we compare our results with previous works. For a general set of couplings of the light scalar to Standard Model fields, we provide a public code, {\tt hipsofcobra}, to compute the decay widths.

    hep-phhep-ex20 citations
15. 15*

    Small Neutrino Masses from a Decoupled Singlet Scalar Field

    Jongkuk Kim🇰🇷 · Seong-Sik Kim🇰🇷 · Hyun Min Lee🇰🇷 · Rojalin Padhan🇰🇷

    We propose a unified solution with $Z_4$ discrete symmetry for small neutrino masses and stability of dark matter. The Standard Model is extended with an inert doublet scalar, a dark singlet scalar, a spurion scalar and right-handed neutrinos, which all transform nontrivially under $Z_4$. After the $Z_4$ symmetry is broken to $Z_2$ by the VEV of the spurion, much below the mass scale of the dark singlet scalar, a small lepton number violating coupling for the inert doublet is generated at tree level, so small neutrino masses are obtained at one-loops for relatively light new fields. We discuss the important roles of the $Z_4$ symmetry for neutrino masses, dark matter physics and thermal leptogenesis.

    hep-phPLB(2025)·8 citations
16. 16*

    Dimuon and ditau production in photon-photon collisions at next-to-leading order in QED

    Hua-Sheng Shao🇫🇷 · David d'Enterria🇨🇭

    Next-to-leading-order (NLO) quantum electrodynamics (QED) corrections to the production of muon and tau pairs in photon-photon collisions, $\gamma \gamma \to {\mu }^{+}{\mu }^{-},{\tau }^{+}{\tau }^{-}$, are calculated in the equivalent photon approximation. We mostly consider $\gamma \gamma$ processes in ultraperipheral collisions of hadrons at the LHC, but the $\gamma \gamma \to {\tau }^{+}{\tau }^{-}$ process in ${\mathrm{e}}^{+}{\mathrm{e}}^{-}$ collisions at LEP is also discussed. The NLO terms are found to modify the total fiducial cross sections by up to 5%, increasing the tails of the dilepton acoplanarity and transverse momentum distributions, and depleting by up to 15% the yields at high masses, with respect to the leading-order predictions including the very small virtuality of the colliding photons. At the LHC, the calculations obtained with the charge form factor for protons and lead ions including the NLO QED corrections improve the data--theory agreement for all measured differential distributions, and prove an indispensable ingredient for the extraction of precision quantities in photon-photon processes, such as the anomalous magnetic moment of the tau lepton.

    hep-phhep-exnucl-exnucl-thJHEP(2025)·22 citations
17. 17*

    On the collider-testability of the type-I seesaw model with 3 right-handed neutrinos

    Marco Drewes🇧🇪 · Yannis Georis🇧🇪 · Juraj Klarić🇧🇪 · Antony Wendels🇫🇷

    If any heavy neutral leptons are discovered in accelerator-based experiments, key questions will involve their possible connection to neutrino masses or leptogenesis. Working in a renormalisable extension of the Standard Model by three right-handed neutrinos, we address the question of how much information about the fundamental model parameters can be obtained by measuring the branching ratios in the decays of the heavy neutral leptons into individual SM generations. We find that, provided that these branching ratios could be measured with arbitrary precision and assuming kinematically distinguishable right-handed neutrinos, they can be sufficient to pin down all 18 parameters of the model when supplemented with light neutrino oscillation data. When considering a finite statistical uncertainty comparable to that which can be achieved by future lepton colliders like FCC-ee or CEPC in the mass range of tens of GeV, some parameter degeneracies remain, but measurements would still provide powerful consistency checks of the model. In the sub-GeV range a good sensitivity to individual model parameters can be expected for SHiP and potentially for DUNE. This shows the potential of these experiments to not only discover heavy neutral leptons, but play an important role in understanding their role in particle physics and cosmology.

    hep-phJHEP(2025)·12 citations
18. 18*

    Exploration to early universe by Josephson Junction Switching Current Detector

    Dan Kondo🇯🇵

    In this paper, we propose a method to probe a Stochastic Gravitational Wave Background (SGWB) with Josephson Junction Switching Current Detector (JJSCD). The sensitivity for the shear can reach $h\simeq 10^{-19}$ realistically, $10^{-21}$ in the near future, $10^{-24}$ optimistically. If we utilize the enhancement factor from the ratio of the frequency, it is possible to reach further below the Big Bang Nucleosynthesis (BBN) bound. It will be interesting if we can access the region to discover a footprint of new physics.

    hep-phcond-mat.mes-hallgr-qcquant-ph1 citation
19. 19*

    Systematic moment expansion for electroweak baryogenesis

    Kimmo Kainulainen🇫🇮 · Niyati Venkatesan🇫🇮

    We present a systematic moment expansion for solving the semiclassical Boltzmann equations for electroweak baryogenesis. The expansion is developed in powers of adiabatic coordinate velocity, and it is used for computing the CP-violating seed asymmetry at the front of the phase transition wall, that sources the eventual baryon asymmetry of the universe (BAU). We implement the method in a benchmark model, with a CP-violating mass arising from a dimension-5 operator coupling the fermion to a singlet scalar field. We find that the higher moment calculations yield a BAU that can significantly differ from the commonly used two-moment approximation. We discuss in detail the underlying approximations in the moment method and propose a new truncation scheme for the expansion, that appears to give more numerically robust results than the previous schemes.

    hep-phastro-ph.COJCAP(2024)·15 citations
20. 20*

    Revisiting Neutrino Masses In Clockwork Models

    Aadarsh Singh🇮🇳

    In this paper, we have studied a mechanism that naturally produces hierarchical masses using fine cancellation rather than widely used suppression mechanisms as in seesaw, clockwork or randomness-assisted localization models. We have also looked at various variants of the clockwork model and provided analytical expressions for their 0 modes. Few generalizations of clockwork models such as generalized CW and next to nearest neighbour interaction CW have already been explored by a few authors. All the variants of CW models have the same underlying principle i.e., suppression. In this study, it was found that non-local CW models relaxes the $\left|q\right|>1$ constraint of ordinary CW models to produce localization. We also made a comparison among them and have shown that in some scenarios variants of CW are more efficient than ordinary CW. Additionally, the fine-cancellation (precision-prune) mechanism is depicted within the framework of the extra dimension picture. Finally, some phenomenological signatures of all these models are also discussed along with their benchmark points.

    hep-phEPJC(2025)·2 citations
21. 21*

    TMD factorization bridging large and small x

    Swagato Mukherjee🇺🇸 · Vladimir Skokov🇺🇸 · Andrey Tarasov🇺🇸 · Shaswat Tiwari🇺🇸

    QCD factorization takes different forms in the large-x and small-x regimes. At large-x, collinear factorization leads to the DGLAP evolution equation, while at small-x, rapidity factorization results in the BFKL equation. To unify these different regimes, a new TMD factorization based on the background field method is proposed. This factorization not only reduces to CSS and DGLAP in the large-x limit and BFKL in the small-x limit, but also defines a general evolution away from these regimes.

    hep-phPoS(2025)·0 citations
22. 22*

    Scaling properties of elastic pp cross-section

    Michal Praszalowicz🇵🇱 · Cristian Baldenegro🇮🇹 · Christophe Royon🇺🇸 · Anna M. Stasto🇺🇸

    We show that the elastic differential $pp$ cross-section has a unique universal property that the ratio of bump-to-dip position is constant from the energies of the ISR to the LHC. We explore this property to compare Geometric Scaling present at the ISR with the recently proposed scaling law at the LHC. We argue that at the LHC, within present experimental uncertainties, there is fact a family of scaling laws.

    hep-phPoS(2025)·1 citation
23. 23*

    First order electroweak radiative corrections to the decay of the polarised $W$ boson

    Maria Naeem🇪🇪 · Stefan Groote🇪🇪

    Analytic results for the next-to-leading order electroweak radiative corrections to the decay of the polarised $W$ boson into a pair of heavy quarks are presented. Finite fermion masses are taken into account throughout this calculation, and in performing the collinear limit for the final quark states and all light fermions taking part in this process, the importance of mass effects is demonstrated. This gives hints for the deviation of the total decay rate and the branching ratios into massive fermions between experimental measurements and theoretical predictions.

    hep-phPRD(2025)·2 citations
24. 24*

    Imprints of supersymmetry at a future Z factory

    Simon Knapen🇺🇸 · Kevin Langhoff🇺🇸 · Zoltan Ligeti🇺🇸

    We study the discovery potential of Z branching ratios due to contributions induced by the MSSM electroweak sector, assuming that the squarks and gluinos are heavy. Precision measurements at a future Z factory would yield sensitivity to MSSM that is complementary to direct searches at the LHC, provided that the systematic uncertainties can be reduced to a level comparable to the expected statistical uncertainties.

    hep-phPRD(2025)·6 citations
25. 25*

    Dark photon distortions of NO$\nu$A and T2K neutrino oscillations

    Gonzalo Alonso-Álvarez🇨🇦 · James M. Cline🇨🇦 · Benoit Laurent🇨🇦 · Ushak Rahaman🇨🇦

    Dark photons coupling to $L_{\mu }-L_{\tau }$ lepton number difference are a highly studied light dark matter candidate, with potential to be discovered through their impact on terrestrial neutrino oscillation experiments. We re-examine this in the light of claimed tensions between the NO$\nu$A and T2K long baseline experiments, also taking into account data from the MINOS experiment. We obtain leading limits on the $L_{\mu }-L_{\tau }$ gauge coupling $g^{\prime }$ versus dark photon mass $m_{A^{\prime }}$, and find no statistically significant alleviation of the tension from inclusion of the new physics effect.

    hep-phastro-ph.COhep-exEPJC(2025)·6 citations
26. 26*

    Imaging the Wakes of Jets with Energy-Energy-Energy Correlators

    Hannah Bossi🇺🇸 · Arjun Srinivasan Kudinoor🇺🇸 · Ian Moult🇺🇸 · Daniel Pablos🇪🇸 · Ananya Rai🇺🇸 · Krishna Rajagopal🇺🇸

    As the partons in a jet propagate through the quark-gluon plasma (QGP) produced in a heavy-ion collision, they lose energy to, kick, and are kicked by the medium. The resulting modifications to the parton shower encode information about the microscopic nature of QGP. The momentum and energy lost by the parton shower are gained by the medium and, since QGP is a strongly coupled liquid, this means that the jet excites a wake in the droplet of QGP. After freezeout, this wake becomes soft hadrons with net momentum in the jet direction meaning that reconstructed jets include hadrons originating from both the modified parton shower and its wake. This makes it challenging to find an unambiguous experimental view of the response of a droplet of QGP to a jet. Recent years have seen significant advances in the understanding of the substructure of jets using correlation functions of the energy flux operator. So far, such studies have focused primarily on the two-point correlator, which serves to identify the angular scale of the underlying dynamics. Higher-point correlators hold the promise of mapping out the dynamics themselves. We perform the first study of the shape-dependent three-point energy-energy-energy correlator in heavy-ion collisions. Using the Hybrid Model to simulate the interactions of high energy jets with QGP, we show that hadrons originating from wakes are the dominant contribution to the three-point correlator in the regime where the three points are well-separated in angle, forming a roughly equilateral triangle. This equilateral region of the correlator is far from the region populated by collinear vacuum emissions, making it a canvas on which jet wakes can be imaged. Our work is a key step towards the systematic use of energy correlators to image and unravel the dynamical response of a droplet of QGP to a passing jet, and motivates many experimental and theoretical studies.

    hep-phhep-thnucl-exnucl-thJHEP(2024)·74 citations
27. 27*

    Anisotropic charge transport in strongly magnetized relativistic matter

    Ritesh Ghosh🇺🇸 · Igor A. Shovkovy🇺🇸

    We investigate electrical charge transport in hot magnetized plasma using first-principles quantum field theoretical methods. By employing Kubo's linear response theory, we express the electrical conductivity tensor in terms of the fermion damping rate in the Landau-level representation. Utilizing leading-order results for the damping rates from a recent study within a gauge theory, we derive the transverse and longitudinal conductivities for a strongly magnetized plasma. The analytical expressions reveal drastically different mechanisms that explain the high anisotropy of charge transport in a magnetized plasma. Specifically, the transverse conductivity is suppressed, while the longitudinal conductivity is enhanced by a strong magnetic field. As in the case of zero magnetic field, longitudinal conduction is determined by the probability of charge carriers to remain in their quantum states without damping. In contrast, transverse conduction critically relies on quantum transitions between Landau levels, effectively lifting charge trapping in localized Landau orbits. We examine the temperature and magnetic field dependence of the transverse and longitudinal electrical conductivities over a wide range of parameters and investigate the effects of a nonzero chemical potential. Additionally, we extend our analysis to strongly coupled quark-gluon plasma and study the impact of the coupling constant on the anisotropy of electrical charge transport.

    hep-phhep-thnucl-thEPJC(2024)·10 citations
28. 28*

    Axions in Andromeda: Searching for Minicluster -- Neutron Star Encounters with the Green Bank Telescope

    Liam Walters🇺🇸 · Jordan Shroyer🇺🇸 · Madeleine Edenton🇺🇸 · Prakamya Agrawal🇺🇸 · Bradley Johnson🇺🇸 · Bradley J. Kavanagh🇪🇸 · David J. E. Marsh🇬🇧 · Luca Visinelli🇨🇳

    The QCD axion and axion-like particles are compelling candidates for galactic dark matter. Theoretically, axions can convert into photons in the presence of a strong external magnetic field, which means it is possible to search for them experimentally. One approach is to use radio telescopes with high-resolution spectrometers to look for axion-photon conversion in the magnetospheres of neutron stars. In this paper, we describe the results obtained using a novel approach where we used the Green Bank Telescope (GBT) to search for radio transients produced by collisions between neutron stars and dark matter clumps known as axion miniclusters. We used the VErsatile GBT Astronomical Spectrometer (VEGAS) and the X-band receiver (8 to 10 GHz) to observe the core of Andromeda. Our measurements are sensitive to axions with masses between 33 and 42 $\mu$eV with $\Delta$$m_a$ = 3.8$\times 10^{-4}$ $\mu$eV. This paper gives a description of the search method we developed, including observation and analysis strategies. Given our analysis algorithm choices and the instrument sensitivity ($\sim$2 mJy in each spectral channel), we did not find any candidate signals greater than 5$\sigma$. We are currently implementing this search method in other spectral bands.

    ↳ astro-ph.COhep-phPRD(2024)·14 citations
29. 29*

    First lattice QCD calculation of $J/\psi$ semileptonic decay containing $D$ and $D_s$ particles

    Yu Meng🇨🇳 · Jin-Long Dang🇨🇳 · Chuan Liu🇨🇳 · Xin-Yu Tuo🇺🇸 · Haobo Yan🇨🇳 · Yi-Bo Yang🇨🇳 · Ke-Long Zhang🇨🇳

    We perform the first lattice calculation on the semileptonic decay of $J/\psi$ using the (2+1)-flavor Wilson-clover gauge ensembles generated by CLQCD collaboration. Three gauge ensembles with different lattice spacings, from 0.0519 fm to 0.1053 fm, and pion masses, $m_{\pi }\sim$ 300 MeV, are utilized. After a naive continuum extrapolation using three lattice spacings, we obtain $\mathrm{Br}(J/\psi \to D_{s}e{\nu }_e)=1.90(6)(5{)}_{V_{cs}}\times 10^{-10}$ and $\mathrm{Br}(J/\psi \to De{\nu }_e)=1.21(6)(9{)}_{V_{cd}}\times 10^{-11}$, where the first errors are statistical, and the second come from the uncertainties of CKM matrix element $V_{cs(d)}$. The ratios of the branching fractions between lepton $\mu$ and $e$ are also calculated as $R_{J/\psi }(D_s)=0.97002(8)$ and $R_{J/\psi }(D)=0.97423(15)$ after performing a continuum limit including only $a^2$ term. The ratios provide necessary theoretical support for the future experimental test of lepton flavor universality.

    ↳ hep-lathep-exhep-phPRD(2024)·20 citations
30. 30*

    Functional Renormalization Group analysis of the quark-condensation pattern on the Fermi surface: A simple effective-model approach

    Kie Sang Jeong🇩🇪 · Fabrizio Murgana🇩🇪 · Ashutosh Dash🇩🇪 · Dirk H. Rischke🇩🇪

    A simple effective model for the intermediate-density regime is constructed from the high-density effective theory of quantum chromodynamics (QCD). In the effective model, under a renormalization-group (RG) scaling towards low momenta, the original QCD interactions lead to four-quark contact interactions for the relevant quark and hole modes around the Fermi surface. The contact interaction in the scalar channel can be traced back to zero-sound-type collinear quark scattering near the Fermi surface in an instanton background. The quark and hole states in opposite directions of a given Fermi velocity form the collective scalar bosonic mode $\sigma$. The magnitude of $\sigma$ is investigated via the non-perturbative Functional Renormalization Group (FRG) evolution of the effective average action from the ultraviolet (UV) to the infrared (IR). In the mean background-field approximation for $\sigma$, nontrivial minima ($\bar{\sigma }\ne 0$) are found in the IR limit of the effective average action. A nonvanishing $\bar{\sigma }$ corresponds to condensation of quark and hole states in opposite directions of a given Fermi velocity, in a thin shell-like structure in momentum space around the Fermi surface. This looks similar to the shell-like baryon distribution in momentum space assumed in the quarkyonic-matter concept. However, when including a dynamic bosonic $\sigma$-mode in the RG flow, we find that its diffusive nature destroys the quark-hole condensate, i.e., the IR potential does not show any minima beyond the trivial one.

    ↳ nucl-thhep-phPRD(2025)·6 citations
31. 31*

    Cross-correlations of the Cosmic Neutrino Background: HR-DEMNUni simulation analysis

    Beatriz Hernández-Molinero🇪🇸 · Matteo Calabrese🇮🇹 · Carmelita Carbone · Alessandro Greco🇺🇸 · Raul Jimenez🇪🇸 · Carlos Peña Garay🇪🇸

    We use the high-resolution HR-DEMNUni simulations to compute cross-correlations of the Cosmic Neutrino Background quantities, like neutrino density, deflection angle, and velocity, with other quantities, like cold dark matter density and effective weak lensing convergence, by accounting for the space-time delay between signals on Earth. We provide this to theoretically illustrate how much can be learned from these cross-correlation signals, once the cosmic neutrino background is detected with instruments in multiple locations. Against a naive expectation of null cross-correlation, we show that the signal is non zero, specially at the largest scales. We also discuss the scenario of co-located cross-correlations between dark matter, weak lensing and a future neutrino-induced photon emission signal. As cross-correlations will be comparable to auto-correlations of the cosmic neutrino background itself and are less affected by cosmic variance and shotnoise, these might be the ones to be measured first. Our predictions thus provide the imprint of what cosmological massive neutrinos, with total mass $\sum m_{\nu }\sim 0.1$ eV, should look like from cosmological observations.

    ↳ astro-ph.COhep-phJCAP(2025)·0 citations
32. 32*

    Dissecting polytopes: Landau singularities and asymptotic expansions in $2\to 2$ scattering

    Einan Gardi🇬🇧 · Franz Herzog🇬🇧 · Stephen Jones🇬🇧 · Yao Ma🇨🇭

    Parametric representations of Feynman integrals have a key property: many, frequently all, of the Landau singularities appear as endpoint divergences. This leads to a geometric interpretation of the singularities as faces of Newton polytopes, which facilitates algorithmic evaluation by sector decomposition and asymptotic expansion by the method of regions. Here we identify cases where some singularities appear instead as pinches in parametric space for general kinematics, and we then extend the applicability of sector decomposition and the method of regions algorithms to such integrals, by dissecting the Newton polytope on the singular locus. We focus on $2\to 2$ massless scattering, where we show that pinches in parameter space occur starting from three loops in particular nonplanar graphs due to cancellation between terms of opposite sign in the second Symanzik polynomial. While the affected integrals cannot be evaluated by standard sector decomposition, we show how they can be computed by first linearising the graph polynomial and then splitting the integration domain at the singularity, so as to turn it into an endpoint divergence. Furthermore, we demonstrate that obtaining the correct asymptotic expansion of such integrals by the method of regions requires the introduction of new regions, which can be systematically identified as facets of the dissected polytope. In certain instances, these hidden regions exclusively govern the leading power behaviour of the integral. In momentum space, we find that in the on-shell expansion for wide-angle scattering the new regions are characterised by having two or more connected hard subgraphs, while in the Regge limit they are characterised by Glauber modes.

    ↳ hep-thhep-phJHEP(2024)·36 citations
33. 33*

    Schwinger vs Coleman: Magnetic Charge Renormalization

    Joshua Newey🇺🇸 · John Terning🇺🇸 · Christopher B. Verhaaren🇺🇸

    The kinetic mixing of two U(1) gauge theories can result in a massless photon that has perturbative couplings to both electric and magnetic charges. This framework can be used to perturbatively calculate in a quantum field theory with both kinds of charge. Here we re-examine the running of the magnetic charge, where the calculations of Schwinger and Coleman sharply disagree. We calculate the running of both electric and magnetic couplings and show that the disagreement between Schwinger and Coleman is due to an incomplete summation of topological terms in the perturbation series. We present a momentum space prescription for calculating the loop corrections in which the topological terms can be systematically separated for resummation. Somewhat in the spirit of modern amplitude methods we avoid using a vector potential and use the field strength itself, thereby trading gauge redundancy for the geometric redundancy of Stokes surfaces. The resulting running of the couplings demonstrates that Dirac charge quantization is independent of renormalization scale, as Coleman predicted. As a simple application we also bound the parameter space of magnetically charged states through the experimental measurement of the running of electromagnetic coupling.

    ↳ hep-thhep-phJHEP(2024)·2 citations
34. 34*

    Searches for ultra-high energy gamma-ray at the Pierre Auger Observatory and implications on super-heavy dark matter

    Olivier Deligny (for the Pierre Auger Collaboration)🇫🇷

    The first interactions of photon-induced showers are of electromagnetic nature, and the transfer of energy to the hadron/muon channel is reduced with respect to the bulk of hadron-induced showers. This results in a lower number of secondary muons. Additionally, as the development of photon showers is delayed by the typically small multiplicity of electromagnetic interactions, their maximum of shower development is deeper in the atmosphere than for showers initiated by hadrons. These salient features have enabled searches for photon showers at the Pierre Auger Observatory. They have led to stringent upper limits on ultra-high-energy gamma-ray fluxes over four orders in magnitude in energy. These limits are not only of considerable astrophysical interest, but they also allow us to constrain beyond-standard-physics scenarios. For instance, dark matter particles could be superheavy, provided their lifetime is much longer than the age of the universe. Constraints on specific extensions of the Standard Model of particle physics that meet the lifetime requirement for a superheavy particle will be presented. They include limits on instanton strength as well as on mixing angle between active and sterile neutrinos.

    ↳ astro-ph.HEhep-phJ.Phys.Conf.Ser.(2025)·1 citation

* 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.