HEP Phenomenology·hep-ph

Wed·Aug 12, 2026Wednesday·August 12, 2026

33 papers—29 primary·4 cross-listed

01
Mysterious Transients in the Palomar Observatory Sky Survey (POSS-1) as profound manifestation of the Dark Matter physics
Ariel Zhitnitsky🇨🇦
Transient star-like objects of unknown origin have been identified in the first Palomar Observatory Sky Survey (POSS-1) as part of the Vanishing and Appearing Sources during a Century of Observations (VASCO) project. The source of the transients recorded by POSS-1 remains unknown, which is the warrant to coin the observed phenomena as Mysterious Transients (MT). We advocate an idea that the dark matter (DM) in form of the axion quark nuggets (AQN) made of standard model quarks (or antiquarks) and gluons, similar to the old idea of the Witten's strangelets, could {\it simultaneously} explain {\it all } the observed MT signals (including very short time scale for flash itself, association with nuclear test timing, observed alignments of several MT events, correlation with UAP reports, etc) collected or recorded for many years. Essentially we argue that the MT is a cousin of Ball Lightning (BL) events, also observed for centuries, without commonly accepted physics explanation. The basic parameters of this model (such as the typical baryon charge of the nuggets) had been fixed long ago by explaining the observed excess of radiation at variety of scales: from galactic to the solar, to local Earth's environments. In this work we use the same framework with the same set of parameters to study the observed MT phenomena. We also suggest several tests which substantiate or refute our proposal. We also present some suggestions on type of instruments required to study this specific (and well defined) type of the UAP events representing the cousins of BL and MT events in the AQN framework.
hep-phastro-ph.COastro-ph.EPphysics.ao-ph0 citations
02
Archimedean Seesaw: Small Neutrino Masses and Large Lepton-number Violation
Tao Han🇺🇸 · Alejandro Ibarra🇩🇪 · Subhojit Roy🇺🇸 · Martina Sabová🇩🇪
Contrary to the common lore that observable lepton-number violation (LNV) is inevitably suppressed by tiny neutrino masses, we identify a class of seesaw models in which arbitrarily large LNV can naturally coexist with sub-eV neutrino masses. We construct a symmetry-protected texture-zero structure in the neutrino Yukawa couplings and heavy Majorana mass matrix that gives rise to the required accidental symmetry, thereby protecting the light neutrinos from acquiring mass even in the presence of arbitrarily large LNV in the heavy sector. Small neutrino masses arise naturally from lifting the texture-zero structure while preserving the underlying symmetry. The resulting framework offers a rich and experimentally accessible phenomenology, predicting Heavy Neutral Leptons with sizeable active-sterile mixing over a broad range of experimentally accessible masses, giving rise to observable LNV signatures at collider and intensity-frontier experiments.
hep-phhep-ex1 citation
03
Electroweak precision observables at NLL order in the SMEFT
Ulrich A. Haisch🇩🇪 · Ben A. Stefanek🇪🇸
Electroweak precision observables (EWPO) remain among the most powerful indirect probes of physics beyond the Standard Model (BSM), and future $e^{+} e^{-}$ colliders are expected to substantially enhance their sensitivity. Within the framework of the Standard Model Effective Field Theory (SMEFT), we show how EWPO predictions can be systematically improved to next-to-leading-logarithmic (NLL) accuracy by combining fixed-order tree-level and one-loop matching with two- and one-loop renormalization-group evolution. We derive NLL expressions that encode the full dependence on all 210 independent Wilson coefficients and illustrate their impact through fits to both current and projected collider measurements. This work provides a basis for global SMEFT analyses at NLL precision, thereby maximizing the indirect reach to BSM physics through EWPO measurements. The phenomenological relevance of this framework is illustrated explicitly in both the custodial Randall-Sundrum model and a custodial composite Higgs model.
hep-ph0 citations
04
Strongly Coupled Soft Functions
Bruno Scheihing-Hitschfeld🇺🇸 · Zhiquan Sun🇺🇸
The renormalization of operators built out of Wilson lines that meet at an angle (cusp) involve what is known as the cusp anomalous dimension, a universal object appearing in many processes in QCD due to the divergences from gluonic interactions. In this paper, we consider the vacuum expectation value of a pair of cusped Wilson lines separated in the transverse direction. This configuration can be related to a simple observable in heavy quark transverse momentum-dependent (TMD) fragmentation as well as the TMD soft function. We compute the expectation values of Wilson loops in $N = 4$ super Yang-Mills theory at strong coupling via the AdS/CFT correspondence, an approach complementary to perturbative calculations of the cusp anomalous dimension. We first present a thorough analysis, directly in Minkowski signature, of the Nambu-Goto action and its saddle points for a Wilson line configuration with a single cusp. We find that there are two different classes of saddle points whose contributions dominate different regions of parameter space. We calculate the cusp anomalous dimension $Γ_{cusp} [Δ η, Δ θ]$ for the whole range of $Δ η$ from this setup, focusing on the cases $Δ θ = 0$ and $Δ θ = π$ , and compare it with previous results in literature. We then use the techniques we developed to compute the expectation value of the two-cusp Wilson loop with transverse separation, and determine the profile of the transverse coordinate on the extremal surface in the large rapidity limit. We discuss the possible generalizations of our setup and results to soft functions in other gauge theories with a holographic dual.
hep-ph0 citations
05
A $U (1)_{(B - L)_{3}}$ model for dark matter and the $B^{+} \to K^{+} ν ν ˉ$ excess reported by Belle II
MohammadAli Abri🇮🇷 · Yasaman Farzan🇮🇷
We explore the $U (1)_{(B - L)_{3}}$ gauge symmetry under which only third generation fermions are charged. The cancelation of the $[U (1)_{(B - L)_{3}}]^{3}$ anomaly requires a chiral fermion, $χ_{L}$ , singlet under the gauge group but charged under $U (1)_{(B - L)_{3}}$ . This chiral fermion can play the role of thermal dark matter with a relic abundance set via the freeze-out scenario through the annihilation to pairs of the third generation fermions. In the quark mass basis, the new gauge boson will have off-diagonal couplings to the $b$ and $s$ quarks which can lead to a new contribution to $B^{+} \to K^{+} ν_{τ} ν ˉ_{τ}$ . We discuss the relevant bounds from the LHC searches for a new gauge boson, dark matter searches, electroweak precision data, $Υ$ decay, the CKM matrix and the $B_{s}^{0} - B ˉ_{s}^{0}$ mixing. We entertain the possibility of explaining the $B^{+} \to K^{+} ν ν ˉ$ excess recently reported by Belle II within this model.
hep-phastro-ph.HEhep-ex0 citations
06
Precision Tests of SM and new physics with the COHERENT Ge-mini and TEXONO data
Tousib Ahmed🇮🇳 · Ayan Chattaraj🇮🇳 · Anirban Majumdar🇮🇳 · Newton Nath🇮🇳 · Rahul Srivastava🇮🇳
A comprehensive numerical analysis of the latest germanium based CE $ν$ NS data from the COHERENT Ge-mini and TEXONO experiments has been conducted to test the Standard Model (SM) and search for new physics. By combining CE $ν$ NS and E $ν$ NS signals with a consistent treatment of detector effects and systematic uncertainties, we obtain a low energy determination of the weak mixing angle from COHERENT Ge-mini, in agreement with the SM prediction. We derive novel constraints on neutrino electromagnetic properties, including the magnetic moment, millicharge, charge radius, and anapole moment, with TEXONO providing particularly competitive bounds. Inclusion of E $ν$ NS, significantly improves the sensitivity to the neutrino millicharge by up to three orders of magnitude. We also investigated light scalar and vector mediators, finding striking complementarity between reactor and stopped pion sources across different mediator mass regimes. Finally, we put bounds on sterile neutral leptons production through transition dipole, scalar, and vector portals, probing masses from the sub MeV to tens of MeV scale. Our results demonstrate that current germanium based CE $ν$ NS experiments provide a powerful low energy laboratory for precision electroweak tests and complementary probes of a broad class of physics beyond the SM.
hep-phhep-ex1 citation
07
Calibrated correlation between heavy-quark masses and Hadronic Vacuum Polarization observables at the precision frontier
Arnau Beltran🇩🇪 · Pere Masjuan🇪🇸 · Antonio Rivera🇪🇸
The theoretical prediction of the muon anomalous magnetic moment $a_{μ}$ depends crucially on the Hadronic Vacuum Polarization (HVP), and the tension between its dispersive and lattice-QCD determinations remains unresolved. We show that part of this puzzle can be addressed in the heavy-quark sector, where both descriptions are theoretically clean, by recognizing that the heavy-quark mass and its contribution to $a_{μ}$ are not independent quantities: both follow from integrals of the same hadronic spectral function, differing only in their integration kernel. Promoting this kernel to a free choice within the relativistic QCD Sum Rules used to determine heavy-quark masses, we break with the conventional notion of a single valid sum rule and instead determine the mass and its HVP contribution simultaneously, from a common, self-consistent framework. This intrinsic construction exploits the anticorrelation between the two quantities to sharpen the final uncertainty, and turns the residual disagreement between the perturbative and hadronic descriptions of the observable into a direct observable-specific diagnostic of residual theory/model dependence, including duality-violation and continuum-modeling effects, unavailable to a determination of the mass alone. We obtain $a_{μ}^{HV P_{c + b}, LO} = (14.46 (13) + 0.3009 (17)) \times 1 0^{- 10}$ at leading and $a_{μ}^{HV P_{c + b}, NL O_{a, b}} = (- 0.5738 (95) - 0.01822 (13)) \times 1 0^{- 10}$ at next-to-leading order, for charm and bottom contributions, respectively. We compare our next-to-leading-order results with its first available lattice determination, finding good agreement in the charm sector. As a byproduct, we obtain $m^_{c} (m^_{c}) = 1267.1 (6.8)$ MeV and $m^_{b} (m^_{b}) = 4182.3 (7.2)$ MeV, with unprecedented phenomenological precision.
hep-phhep-lat1 citation
08
Heavy neutral leptons beyond the BBN bound: probing the lepton asymmetry of the Universe
Kensuke Akita🇯🇵 · Maksym Ovchynnikov🇨🇭 · Vsevolod Syvolap🇪🇸
Hadronically decaying particles with lifetimes $τ ≳ 0.02 s$ are excluded by Big Bang Nucleosynthesis almost independently of their abundance: the mesons from their decays convert protons into neutrons faster than the reverse, and helium is overproduced. For heavy neutral leptons (HNLs), this blankets the couplings the upcoming accelerator searches can reach. We propose a scenario with large lepton flavor asymmetries in which HNLs evade it. A Dirac HNL decays into $π^{+}$ and its antiparticle into $π^{-}$ , so an asymmetry between the two populations injects an excess of $π^{+}$ , which converts the neutrons back to their standard abundance, while a cancellation between the asymmetries and the HNL decays keeps the shift in $N_{eff}$ small. This opens the parameter space with $m_{l} + m_{π} ≲ m_{N} ≲ 1 GeV$ and $τ_{N} ≲ 1 s$ , including a substantial region within the reach of SHiP. A discovery there, combined with the BBN and CMB observables, would fix the primordial flavor asymmetries up to one remaining direction. The relic neutrino background and a possibly first-order cosmic QCD transition, a source of gravitational waves, may probe that direction, and with it the lepton asymmetry of the Universe.
hep-phastro-ph.CO0 citations
09
Scalar baryons in neutron stars
Julian Heeck🇺🇸 · Yu Zhi🇺🇸
Neutron stars have baryon chemical potentials that can exceed the neutron mass, providing favorable conditions to convert neutrons to new particles carrying baryon number, even if those processes are kinematically forbidden in vacuum. We study the effect of GeV-scale scalars with baryon number on neutron stars' equation of state and show that non-perturbatively large repulsive self-couplings are required to support the observed two-solar-mass neutron stars. We also study potentials with attractive self-interactions, which can trigger scalar production even for masses above the chemical potential and resemble Coleman's Q-matter.
hep-phastro-ph.CO0 citations
10
QCD-Matched Gluonic Response in Heavy-Quarkonium Born-Oppenheimer EFT: Locality, Channel Factorization, and the Peskin Limit
Arkadiy I. Syamtomov🇺🇦
We formulate a source-dependent QCD-to-BOEFT matching for the gluonic response of a stable compact heavy-quarkonium state. The matched complementary-space resolvent preserves coupled Born-Oppenheimer dynamics, while an exact Feshbach decomposition separates channels retained explicitly from sectors integrated out at the next matching step. Spectral separation, kernel analyticity, and joint propagation-source bounds provide sufficient conditions for a local channel-factorized OPE; otherwise low-energy BO poles and cuts remain dynamical. The weak-coupling pNRQCD response is recovered as a limiting reference problem. With the additional leading- $E 1$ , large- $N_{c}$ /free-octet assumptions, the source-weighted spectral measure reproduces the established Bhanot-Peskin electric moments and dissociation cut. For a Coulombic spin-singlet $1 S$ state we also obtain the sequential- $M 1$ contribution $c_{B, GG}^{(1) ij} = 5 π α_{s}^{2} (c_{F} V_{iso}^{(s)})^{2} δ^{ij} /16$ and the covariant-kinetic seagull contribution $c_{B, dia}^{(1) ij} = - π α_{s}^{2} δ^{ij} /4$ . These are identifiable components, not the complete magnetic matching coefficient.
hep-phhep-th0 citations
11
Extraction of baryon number susceptibilities at finite density from heavy-ion collisions
Grégoire Pihan🇺🇸 · Roman Poberezhniuk🇺🇸 · Volodymyr A. Kuznietsov🇺🇸 · Volodymyr Vovchenko🇺🇸
We present, to our knowledge, the first Bayesian extraction of baryon number susceptibilities of QCD matter at finite baryon density from heavy-ion collision data on proton number cumulants. The framework embeds arbitrary equation-of-state susceptibilities $χ_{n}^{B}$ into realistic hydrodynamic particlization hypersurfaces through maximum-entropy freeze-out, maps the resulting (anti)baryon fluctuations onto protons, applies the experimental kinematic acceptance, and accounts for exact baryon number conservation. Applying the framework to measurements of (net-)proton number fluctuations in 0--5\% central Au-Au collisions from the RHIC Beam Energy Scan in the collider mode, we extract, at each collision energy, the second-order susceptibility normalized by the hadron resonance gas value, $χ_{2}^{B} / χ ˉ_{2}^{B}$ , and the higher-order susceptibility ratios $χ_{3}^{B} / χ_{1}^{B}$ and $χ_{4}^{B} / χ_{2}^{B}$ . We obtain tight constraints on $χ_{2}^{B}$ , with extracted values in quantitative agreement with lattice QCD based estimates along the chemical freeze-out line for $μ_{B} ≲ 300$ ~MeV. At larger $μ_{B}$ , the extracted values indicate an enhancement of baryon number fluctuations relative to the noncritical lattice-based extrapolation and HRG baseline considered here. The third- and fourth-order susceptibilities are only weakly constrained. In particular, we find that the observed nonmonotonic collision-energy dependence of the proton factorial cumulant ratio $C^_{3} / C^_{1}$ can be described without irreducible three- or four-baryon correlations. This behavior emerges from the interplay between the energy dependence of $χ_{2}^{B}$ and exact baryon number conservation.
hep-phnucl-exnucl-th0 citations
12
The near-threshold cross section of $e^{+} e^{-} \to Ω^{-} Ω ˉ^{+}$ : Heavy-flavor rescattering and physics-informed deep learning
Sara Rahmani🇨🇳
Recent precision measurements of the $e^{+} e^{-} \to Ω^{-} Ω ˉ^{+}$ cross section by the BESIII collaboration provide a valuable opportunity to probe complex hadronic rescattering mechanisms. In this work, we investigate a potential structure near the $D_{s} D ˉ_{s}$ threshold using a coupled-channel framework incorporating $Ω Ω ˉ$ , $Ξ Ξ ˉ$ , and $D_{s} D ˉ_{s}$ interactions. The driving potentials are derived from effective Lagrangians respecting heavy quark spin symmetry, chiral symmetry, and hidden local symmetry, and the scattering amplitude is unitarized via the on-shell factorization of the Bethe-Salpeter equation. To go beyond local fits and map theoretical uncertainties, we use a two-step machine-learning framework. First, Simulation-Based Inference with a Mixture Density Network maps the global Bayesian posterior of the effective couplings. Second, to identify the non-perturbative threshold dynamics without the instabilities of traditional root-finding across multiple Riemann sheets, we employ a Cauchy-Riemann Physics-Informed Neural Network (PINN). The network enforces mathematical analyticity, smoothly continuing the real-axis amplitude into the complex energy plane. We isolate a pole at $M = 3.847$ GeV with zero decay width, sitting $89$ ~MeV below the $D_{s}^{-} D ˉ_{s}^{+}$ threshold. The corresponding S-matrix residues show an overwhelming coupling to the $D_{s} D ˉ_{s}$ channel, indicating that the threshold dynamics are driven by a dynamically generated $D_{s}^{-} D ˉ_{s}^{+}$ bound state.
hep-ph0 citations
13
Commensurate Structure of Quark and Lepton Mixing: Eighteenth Powers of One Parameter and a Digital-Clock Quantization of the Unitarity Triangles
Vernon Barger🇺🇸
We identify two commensurate structures in the measured quark and lepton mixing data, one multiplicative and one angular, and their exact relation. With the hierarchy parameter $ε \equiv ∣ V_{u b} ∣^{3/10} = 0.1869 \pm 0.0018$ , the measured Fritzsch--Xing (FX) angles satisfy $sin θ_{u} = ε^{26/18}$ , $sin θ_{d} = ε^{17/18}$ , and $sin θ = ε^{34/18}$ with coefficients within $2.5%$ of unity, and the phase is maximal, $ϕ_{FX} = 92. 3^{\circ} \pm 2. 7^{\circ}$ against $π /2$ . Unit coefficients reproduce the remaining moduli at the percent level and fix the derived Jarlskog invariant, $J = ε^{111/18} sin ϕ_{FX}$ , matching the measured $3.08 (14) \times 1 0^{- 5}$ . The rephasing-invariant image of this structure is a unitarity triangle quantized on the $π /24$ lattice, a digital clock, $(α, β, γ) = (12, 3, 9) \times 7. 5^{\circ}$ , consistent with data at $1 σ$ through $α ≃ ϕ_{FX}$ and the theorem $tan β ≃ ε$ ; degree-level $γ$ confronts $67. 5^{\circ}$ -- $6 8^{\circ}$ . For the leptons, where only the angular structure can act, its PMNS analog, formed from columns $1$ and $3$ , free of Majorana phases, on the same lattice requires $δ_{CP} ≃ 29 6^{\circ}$ in the upper octant or $24 4^{\circ}$ in the lower, testable at DUNE and Hyper-Kamiokande. The quark and lepton triangles share $β = 22. 5^{\circ}$ , measured for quarks, predicted for leptons, and differ by a transfer of two lattice units, with corollary $δ_{CP} ≃ - δ ≃ 29 5^{\circ}$ . The same $ε$ sets the neutrino mass ratio, $r \equiv m_{2} / m_{3} = ε^{19/18}$ , and the PMNS first row follows in powers of $r$ , $(r^{1/9}, r^{1/3}, \frac{3}{2} r)$ , both relations at $0.2 σ$ and testable at JUNO. The analysis is confined to the parameterization level; no dynamics is assumed.
hep-phhep-ex0 citations
14
Event-by-event analysis of chiral charge separation in $p^{↑} +$ Au collisions within an improved AMPT model
Chen Gao🇨🇳 · Gui-Zhen Wu🇨🇳 · Yi Xu🇨🇳 · Wei-Tian Deng🇨🇳
We study the charge separation induced by chiral magnetic effect (CME) in $p^{↑}$ +Au collisions at $s_{N N} = 200$ GeV event-by-event with an improved string-melting AMPT model. In this model, an impact-parameter-dependent formation-time delay is introduced to reduce the peak Bjorken energy density from $\sim$ 2 to $\sim$ 0.3 GeV/fm $^{3}$ and reproduces the illiptic flow $v_{2} (p_{T})$ measured by PHENIX in $p +$ Au simultaneously. The event-by-event CME source, whose quark momentum-exchange fraction scales with $∣ B ∣_{event} /∣ B ∣_{max}$ and is capped at the 7\% value from Au+Au, transmits the field geometry directly to the observable. We find that the initial correlator shows a clear scheme hierarchy tracking $B^{2}$ . The parton cascade preserves $\sim$ 80--90\% of the signal, while coalescence and ART hadronic rescattering dissipate the bulk, leaving $\sim$ 10--30\% in the final state. The $γ_{O S} / γ_{S S}$ splitting remains visible. These results support the use of the inter-scheme difference $Δ γ_{IV} - Δ γ_{II}$ as an essentially background-free CME observable as we proposed in previous work.
hep-phnucl-th0 citations
15
Nucleon electromagnetic form factors in nonlocal chiral effective theory
Y. Salamu🇨🇳 · Alim Ablat🇨🇳
In this paper, we calculate the pion one-loop corrections to the electromagnetic form factors of the nucleon up to $O (p^{4})$ order in the nonlocal framework. To systematically investigate the role of vector-meson dominance in the model, we also include the leading-order nucleon-vector-meson coupling. Owing to the renormalization-scheme dependence of chiral low-energy coupling constants (LECs), we refit these constants to the nucleon magnetic moments, electromagnetic radii, and the $Q^{2}$ -dependence of the electromagnetic form factors. Compared with the previous local analysis, the model results show that, in the nonlocal framework, the $Q^{2}$ -dependence of the electromagnetic form factors in the large- $Q^{2}$ region is significantly improved and are consistent with experimental data.
hep-ph0 citations
16
Probing vorticity and fluctuations in a rotating hadron resonance gas at LHC energy
S. Ipsita Sahoo🇮🇳 · Sanjeebani Biswal🇮🇳 · D. Dutta🇮🇳 · D. K. Mishra🇮🇳
A large vorticity produced in non-central ultra-relativistic heavy-ion collisions induces an effective chemical potential in both partonic and hadronic matter, thereby influencing the quark-hadron transition and its associated properties. In this work, we investigate the influence of rotation on hadron yields within the framework of Hadron Resonance Gas (HRG) model. Our results show that vorticity significantly modifies hadron yields and their ratios. Most notably, rotation enhances the $p / π^{+}$ ratio while suppressing the $K^{+} / π^{+}$ ratio, suggesting that these observables may serve as sensitive probes of the rotational properties of the medium created in heavy-ion collisions. To quantify the effect of rotation, the calculated dependence of the $p / π^{+}$ ratio on vorticity is compared with the centrality dependence of the $p / π$ ratio measured by the ALICE collaboration in Pb+Pb collisions at $s_{_{N N}}$ = 5.02 TeV. From this comparison, we estimate the maximum vorticity produced at freeze-out for different collision centralities. In case of peripheral collisions, the freeze-out vorticity ( $ω$ ) is found to reach an upper bound value of approximately 0.088 GeV, whereas for central collisions it is about 0.028 GeV. Furthermore, we investigate the effect of rotation on fluctuations of conserved quantities and their correlations. This study provides a quantitative framework for assessing the role of rotation in the thermodynamics of hadronic matter and its phenomenological consequences for heavy-ion collisions.
hep-phnucl-exnucl-th0 citations
17
Probing Gluon Linear Polarization with Dihadron Fragmentation in $χ_{b}$ Decays
Zhi-Guo He🇨🇳 · Guanghui Li🇨🇳 · Yang Liu🇨🇳 · Yu-Jie Tian🇨🇳 · Xin-Kai Wen🇨🇳 · Bin Yan🇨🇳
The dihadron fragmentation function (DiFF) of a linearly polarized gluon has not yet been accessed experimentally, leaving an important aspect of spin-dependent gluon hadronization unexplored. We show that, at leading order, the color-singlet decay channel of the $P$ -wave bottomonium state $χ_{b 0}$ produces two energetic gluons with correlated linear polarizations. Within collinear factorization, their fragmentation into separate dihadron pairs generates an Artru--Collins-type angular correlation that provides the first direct probe of the linearly polarized gluon DiFF, while the corresponding semi-inclusive decay rate constrains the unpolarized gluon DiFF. A spectator-model benchmark indicates percent-level asymmetries, potentially within reach of existing Belle data. A dedicated Belle~II data set would substantially improve the statistical precision, enabling more stringent constraints on the kinematic dependence of the linearly polarized gluon DiFF.
hep-phhep-exnucl-exnucl-th1 citation
18
Scaling of soft QGP signatures in relativistic lead, xenon and oxygen collisions in EPOS4
Salman Khurshid Malik🇮🇳 · Fakhar Ul Haider🇮🇳 · Pratibha Bhagat🇮🇳 · Anju Bhasin🇮🇳 · Ramni Gupta🇮🇳
The collective expansion and hydrodynamic evolution in heavy-ion collisions is well-established. However, whether femtometer-scale droplets of QGP are produced in small systems at high energies remains a fundamental open question. Analysis of Pb $-$ Pb collisions at $s_{NN}$ = 5.02 TeV, Xe $-$ Xe at $s_{NN}$ = 5.44 TeV and O $-$ O collisions at $s_{NN}$ = 5.36 TeV using EPOS4 is reported to make predictions and postdictions. The results are compared with ALICE data for Pb $-$ Pb and Xe $-$ Xe collisions. Charged particle multiplicity (d $N_{ch}$ /d $η$ ), transverse-momentum ( $p_{T}$ ) spectra for pions ( $π^{\pm}$ ), kaons ( $K^{\pm}$ ), and protons ( $p (p)$ ) are studied. The inclusion of hadronic afterburner, UrQMD (Ultra-relativistic Quantum Molecular Dynamics) is found to be necessary to correctly describe baryon yields. $p_{T}$ -fluctuations are also studied via normalized $p_{T}$ correlator, $⟨⟨ Δ p_{T, i} Δ p_{T, j} ⟩⟩ / ⟨⟨ p_{T} ⟩⟩$ . Lastly, anisotropic flow harmonics ( $v_{2} {2}$ , $v_{3} {2}$ ) are computed as a function of $p_{T}$ and centrality. Since EPOS4 has not been extensively studied for flow observables, this study thereby provides a non-trivial assessment of its collective dynamics. The results are compared with experiment wherever data is available. Taken together, this study provides a unified description of soft observables from Pb $-$ Pb through Xe $-$ Xe down to O $-$ O and offer quantitative guidance on how such collisions may inform of the properties of the QGP.
hep-phnucl-thPRC(2026)·0 citations
19
Baryogenesis and CMB spectral distortion from Axions
Zhenhao Zhang🇫🇷 · Mingqiu Li🇨🇳 · Sichun Sun🇨🇳
We discuss a mechanism for generating the baryon asymmetry in the early universe. We show that an axion-like particle can modify the related gauge field configurations in the Standard Model, thereby altering their dispersion relations. This change in the Chern-Simons number can source a violation of baryon number. We derive the relationship between the resulting baryon number and the evolution of the axion background. We estimate the baryon asymmetry produced via this mechanism and show that the observed value can be naturally achieved. We also show that axion photon coupling produces Cosmic Microwave Background spectral distortion. Our results show that the resulting distortion approaches a constant at low frequencies, unlike the conventional y-type and $μ$ -type distortions.
hep-phastro-ph.COgr-qchep-th0 citations
20
Evolution of the underlying event and non-extensive thermodynamics in pp collisions from RHIC to LHC energies
Suraj Prasad🇭🇺 · Aditya Nath Mishra🇮🇳 · Guy Paić🇭🇺 · Gergely Gábor Barnaföldi🇭🇺
We investigate the geometrical and thermodynamical aspects of particle production in pp collisions over a broad center-of-mass energy, ranging from $s = 62.4$ GeV to 13 TeV using PYTHIA8. We study the azimuthal dependence of charged-particle production relative to the leading particle. This includes the study of the Tsallis--Pareto parameters extracted from the charged-particle transverse-momentum spectra in fixed $Δ ϕ$ intervals relative to the leading charged particle. The simultaneous analysis of charged-particle multiplicity and event topology demonstrates that the underlying event (UE) dominated region can be extended beyond the conventional transverse side region across RHIC and LHC energies. To further disentangle effects from soft and hard particle production mechanisms, the study is performed in different transverse spherocity and charged-particle flattenicity classes. We demonstrate that the UE region extends beyond the conventional transverse region, validating an enlarged angular interval of $4 0^{\circ} ≲ ∣Δ ϕ ∣ ≲ 14 0^{\circ}$ from RHIC to LHC energies. Event-shape selections reveal that jetty events consistently exhibit larger $q$ and lower $T_{s}$ than isotropic events. The $Δ ϕ$ profiles of charged-particle multiplicity and transverse spherocity remain universal in shape across collision energies despite the strong increase in overall event activity, whereas the Tsallis parameters retain a residual, leading-particle-driven energy dependence in the near- and away-side regions.
hep-phhep-exhep-thnucl-ex+10 citations
21
Superfluid He-4 as Dark Matter Detectors
Zizhou Huang🇨🇳 · Mihaela Parvu🇷🇴 · Dmitry Budker🇩🇪 · Ariel Zhitnitsky🇨🇦 · Konstantin Zioutas🇬🇷
Superfluid helium-4 is an attractive medium for high-sensitivity detection of dark matter (DM) candidates (as well as other particles). There are several collaborations that have built and tested superfluid helium detectors, particularly focusing on the sub-GeV DM mass range. In this paper we discuss a novel idea for detecting Axion (Anti)Quark Nuggets (AQN) by using parasitically the superfluid helium-4 LHC cooling system as a unique large-scale earth bound DM detector. In the case of the AQN, we address the question of propagation in the metal parts surrounding the helium. An AQN induces significant heating around the propagation track that damages the enclosure.
hep-phhep-ex0 citations
22
Monsters and neutron stars
Sourendu Gupta🇮🇳
Using dimensional arguments and other simple estimates, it is pointed out that a branch of nuclei with mass number A>10^7 could be metastable if they have close to maximal isospin. This branch is continuous with neutron stars. The fastest decay mode of these hypothetical metastable nuclei (which we call monsters) is through neutron evaporation. We present an estimate of the lifetime and show it could be more than 100 ps for A>10^{39}. We speculate about their creation in binary neutron star mergers, where we argue that their lifetimes could be extended further, and their presence could be detectable in gravity wave experiments of the near future.
hep-phnucl-th0 citations
23
Gluonic nucleon energy correlators and fracture functions for Color Glass Condensate
Heikki Mäntysaari🇫🇮 · Yu Shi🇨🇳 · Yossathorn Tawabutr🇫🇮 · Xuan-Bo Tong🇫🇮
Nucleon energy correlators (NECs) and fracture functions provide novel tools for probing nucleon and nuclear structure at small $x$ through measurements in the target fragmentation region (TFR) of deep inelastic scattering (DIS). We investigate gluonic NECs and fracture functions using the Color Glass Condensate effective theory at eikonal accuracy. We find that only the unpolarized and linearly polarized gluon components in an unpolarized target are nonvanishing at this order, and that both are determined by the adjoint dipole $S$ -matrix. Furthermore, we show that the linearly polarized gluonic NEC $h_{1}^{t, g}$ generates a characteristic $cos 2 ϕ$ azimuthal asymmetry in the DIS energy pattern in the TFR. Unlike analogous observables in the current fragmentation region, this asymmetry is governed by the ratio of the linearly polarized gluon NEC $h_{1}^{t, g}$ to the unpolarized quark NEC $f_{1}^{q}$ , making it particularly sensitive to the saturation scale. Our numerical analysis shows that this asymmetry exhibits substantial nuclear suppression, providing a novel window into the onset of gluon saturation at the future Electron-Ion Collider.
hep-phnucl-th2 citations
24
TauPolaris: reconstructing tau lepton polarimetric vectors with conditional normalizing flows
Daniel Winterbottom🇬🇧 · Lucas Russell🇬🇧
The kinematics of tau lepton decay products depend on the tau spin, giving access to the spin correlations and CP structure of the process that produced them. The optimal spin observable is the polarimetric vector, which points along the most likely direction of the tau spin. Determining it requires the momenta of the neutrinos produced in the tau decays, which escape detection and must therefore be inferred. We present TauPolaris, a tool for reconstructing tau polarimetric vectors by estimating the undetected neutrino momenta with a conditional normalizing flow. Rather than performing a point regression, the method models the full conditional density of the neutrino kinematics, providing both the most likely configuration for each event and an estimate of its uncertainty. The resolution of the reconstructed spin observables improves on that obtained from networks trained with a mean-squared-error loss. Using simulated LHC proton-proton collisions, including detector resolution effects, we demonstrate the method in three applications. For tau leptons produced in Higgs boson decays, we show that the presence of quantum entanglement can be distinguished from its absence with a significance of at least $4.3 σ$ at the High-Luminosity LHC. We demonstrate an 18% improvement in the sensitivity to CP violation in $H \to τ τ$ decays. Finally, we introduce new variables for suppressing the $Z \to τ τ$ background in Higgs boson searches.
hep-phhep-ex0 citations
25
Multi-Channel Di-Higgs Production in the scNMSSM: From Exotic 8b to Boosted 8tau Signatures at the HL-LHC
Marwa Telba
We investigate multi-channel di-Higgs signal prospects in the semi-constrained Next-to-Minimal Supersymmetric Standard Model (scNMSSM) at large-lambda/low-tan(beta) at the HL-LHC with sqrt(s) = 13.6 TeV and L = 3000 fb^{-1}. Building on our previous work, four benchmark points are selected from 66 viable SM-like candidates, spanning three di-Higgs topologies: exotic multi-b (h1h1 -> 4a1 -> 8b, BP1/BP3), boosted multi-tau (h1h1 -> 4a1 -> 8tau, BP2), and SM-like (BP4). A complete signal simulation chain (MadGraph5_aMC@NLO + Pythia 8.316 + Delphes 3) is employed for 10^5 signal events per benchmark point. Background yields are estimated from published LHC analyses and are used only for indicative sensitivity projections. For the 8b topology (BP1: m_{a1} = 47.4 GeV, BP3: m_{a1} = 51.9 GeV), b-jet efficiencies of epsilon(>=4b) ~ 14% yield S ~ 14,000-16,000 events, potentially compatible with 5-sigma sensitivity under the simplified background model adopted. For the boosted 8tau topology (BP2: m_{a1} = 8.2 GeV), 82.4% of same-a1 tau-pairs have Delta R(tau,tau) < 0.4, below the standard jet cone radius, due to the large Lorentz boost gamma ~ 7.5. This topology yields epsilon(>=2tau) = 38.4%, a factor of ~21 above the SM baseline, but requires dedicated boosted a1 taggers due to irreducible multi-tau backgrounds. BP4 serves as a SM-like reference, consistent with existing HL-LHC HH projections. The Higgs self-coupling modifier kappa_lambda in [0.884, 0.951] is universally suppressed below unity. The boosted a1 topology of BP2 is not covered by any existing ATLAS or CMS di-Higgs search, strongly motivating dedicated sub-jet analysis strategies at the HL-LHC.
hep-ph1 citation
26
Tricritical dynamics in $^{3} He$ - $^{4} He$ mixtures and QCD
Maneesha Pradeep🇮🇳 · Johannes V. Roth🇩🇪 · Lorenz von Smekal🇩🇪
In this paper we study the universal critical dynamics near the tricritical points in $^{3} He$ - $^{4} He$ mixtures and QCD with two massless quark flavors. In particular, we use the real-time formulation of the functional renormalization group to understand how the tricritical region connects the $O (4)$ Model G dynamics of the two-flavor chiral phase transition to that of Model H for the QCD critical point with explicitly broken chiral symmetry. We show that in presence of an additional subdiffusive energy-like density, the tricritical dynamics inherits the strong dynamic scaling of Model G, where the critical fluctuations of order parameter and conserved $O (N)$ charges relax at identical rates. The strong scaling in the planar $O (2)$ case relevant for the $λ$ -line and the tricritical point in the liquid $^{3} He$ - $^{4} He$ mixtures arises as an interesting limiting case. Including the explicit symmetry breaking by the finite light-quark masses in QCD, the energy-like density of the tricritical dynamics mixes linearly with the $Z_{2}$ order parameter to eventually produce the characteristic slow fluctuations of the entropy per baryon near the QCD critical point.
hep-ph0 citations
27
Hilbert Series of Pseudoscalar Mesons: Operators and Sum Rules
Joydeep Chakrabortty🇮🇳 · Sabyasachi Chakraborty🇮🇳 · Siddhartha Karmakar🇮🇳
We construct the complete non-redundant basis of operators built from pseudoscalar mesons using the Hilbert series method, subject to the global flavor symmetry $S U (3)_{L} \times S U (3)_{R} \times S U (2)_{L_{H}} \times S U (2)_{R_{H}}$ , together with the underlying shift symmetry. The SM weak interactions are incorporated systematically by promoting the CKM matrix elements to spurion fields transforming under the global symmetry. The resulting operator basis provides a model-independent parametrization of two- and three-body weak decay amplitudes of heavy mesons, with the corresponding Wilson coefficients serving as reduced hadronic amplitudes. We demonstrate that all amplitude sum rules follow directly from the structure of the operator basis and propose an unfolding procedure that connects the effective operators to their possible ultraviolet origins. Our framework reproduces the known flavor relations while predicting additional identities arising from the symmetry-constrained operator basis.
hep-phhep-exhep-th1 citation
28
QCD Vacuum in an Inhomogeneous Magnetic Field
Prabal Adhikari🇺🇸 · Brian C. Tiburzi🇺🇸
The effect of an inhomogeneous magnetic field on the QCD vacuum is addressed using the framework of chiral perturbation theory. The magnetic field is chosen to be localized along one spatial direction, with a profile for which the underlying quantum mechanical problem is exactly solvable. Particular attention is paid to regularization and renormalization using dimensional regularization. While the non-vanishing gradient of the magnetic field requires additional operators in chiral perturbation theory, their effect occurs at next-to-next-to-leading order in the chiral expansion. Consequently, the magnetic field dependence of equilibrium vacuum observables can be determined at next-to-leading order without undetermined parameters. We compute the zero-temperature free energy and chiral condensate for the inhomogeneous background, both as integrated quantities as well as spatially resolved local observables. Comparison with locally constant approximations enables a direct probe of the spatial response and nonlocal structure of the magnetized QCD vacuum. We additionally derive the induced vacuum current associated with the inhomogeneity of the magnetic field.
hep-phhep-latnucl-th0 citations
29
$∣Δ I ∣ = 3/2$ non-leptonic hyperon decays in covariant baryon chiral perturbation theory
Jie Xu🇨🇳 · Jun-Xu Lu🇨🇳 · Rui-Xiang Shi🇨🇳 · Li-Sheng Geng🇨🇳
Inspired by the recent BESIII measurements of non-leptonic hyperon decays, we reexamine their $∣Δ I ∣ = 3/2$ amplitudes in covariant baryon chiral perturbation theory with the extended-on-mass-shell renormalization scheme. Using the same restricted set of diagrammatic topologies as in the early analyses in heavy baryon chiral perturbation theory, we assess the effects of relativistic corrections, explicit decuplet baryons, different spin- $3/2$ coupling schemes, and pion-loop contributions. Our results show that relativistic effects alone lead to only mild changes, while decuplet contributions, especially in the consistent-coupling scheme, significantly improve the fit quality. Pion-loop contributions further reduce the $χ^{2}$ values. We highlight the importance of the consistent coupling scheme in the decuplet sector for describing the selected $∣Δ I ∣ = 3/2$ amplitudes.
hep-ph0 citations
30
Reconstructing Dark Matter Mass and Discriminating Standard and Non-Standard WIMP-Nucleus Interactions with Paleo-Detectors
Dionysios P. Theodosopoulos🇺🇸 · Katherine Freese🇺🇸 · Chris Kelso🇺🇸 · Patrick Stengel🇸🇮
Paleo-detectors record and retain crystal damage in ancient minerals from nuclear recoils induced by dark matter scattering over geological timescales. Previous studies have shown that paleo-detectors can provide sensitivity to a variety of dark matter (DM) scenarios which is complementary to conventional direct-detection experiments. In this paper, we complete the first detailed study of how well paleo-detectors can reconstruct DM parameters or distinguish between different types of DM interactions with nuclei in the presence of a DM signal, considering both elastic and inelastic DM-nucleus scattering. For representative nuclear recoil track read-out scenarios, we demonstrate that weakly interacting massive particle (WIMP) DM masses can be reconstructed for a variety of Non-Relativistic Effective Field Theory (NREFT) interactions between WIMPs and nuclei. In particular, paleo-detectors are projected to be capable of reconstructing WIMP masses $≲$ 10 GeV, a regime that is challenging for conventional direct-detection experiments; further, we find that paleo-detectors could reconstruct WIMP masses up to 1 TeV for hypothetical signals within their accessible parameter space, extending the mass range over which reconstruction is possible by up to a factor of $\sim 2$ compared with analogous studies of conventional direct-detection experiments. In addition, we demonstrate that paleo-detectors could discriminate between canonical spin-independent or spin-dependent NREFT interactions and non-canonical interactions which can depend on the relative velocity or momentum transferred between the WIMP and nucleus. Specifically, at WIMP masses $≳$ 10 GeV, we project that canonical NREFT interactions can be excluded by paleo-detectors in the cases of nearly all non-canonical interactions without measurement of nuclear recoil direction, which conventional experiments typically require.
↳ astro-ph.COastro-ph.IMhep-exhep-ph+10 citations
31
Approximating Grassmann valued path integrals with radial basis function neural networks
Gábor Balassa🇰🇷
Solving path integrals in quantum field theories often involves the numerical handling of noncommuting Grassmann fields, which is in many cases a highly nontrivial and numerically inefficient task, especially in large systems and at higher dimensions. In this paper a radial basis function type neural network construction is used to approximate fermionic path integrals that include local couplings in their hopping terms. By isolating the interaction terms from the purely fermionic components using a radial basis function expansion, the path integral can be approximated by a few percent accuracy even for very large lattice sizes. The method has been developed and tested using staggered fermions in one, and in two dimensions, through calculating the partition functions, and expectation values.
↳ hep-lathep-phPRD(2026)·0 citations
32
Radiative Signatures from Warp Drives Traveling Through the Earth's Atmosphere
Shaun David Brocus Fell · Abraham Loeb🇺🇸
We investigate the observable signatures of zero ADM mass warp drive spacetimes traversing Earth's atmosphere. Numerical simulations indicate that an aircraft-scale spacetime bubble moving at relativistic velocities would have a pronounced observational signature, where interaction with the atmosphere can produce luminosities exceeding one terawatt. The signature of a spacetime bubble at rest or moving at low velocity relative to the Earth would not generate such extreme luminosities. These results establish observational constraints on spacetime-based propulsion operating within the terrestrial environment and provide a framework for identifying potential high-velocity signatures. In particular, a warp drive traveling through the atmosphere at speeds exceeding approximately 10% of the speed of light would produce a unique brilliant glow.
↳ gr-qcastro-ph.HEhep-ph0 citations
33
Nucleon electromagnetic form-factors in a minimal Gari-Krümpelmann model including the explicit two-pion continuum
Wulf Krümpelmann🇩🇪 · Yong-Hui Lin🇩🇪 · Ulf-G. Meißner🇩🇪
The Gari--Krümpelmann (GK) model provided one of the first semiphenomenological descriptions of the electromagnetic nucleon form-factors over a wide range of momentum transfer. It combined vector-meson dominance at low and intermediate momentum transfer with perturbative-QCD constraints at large momentum transfer. The present work extends this framework by including the dispersive two-pion continuum explicitly in the isovector channel. The two-pion contribution is taken from modern dispersive analyses and embedded into the intrinsic high- $Q^{2}$ structure of the GK ansatz. The physical $ρ$ dynamics is then interpreted as part of the correlated two-pion spectral function. The direct coupling terms remain essential for the transition to the asymptotic regime. This gives a cleaner separation between long-range continuum dynamics, coherent vector-meson contributions, and direct quark-current dynamics. With just 5 parameters, we can describe the large body on form-factor data and differential cross sections from electron-proton scattering in the space-like region.
↳ nucl-thhep-exhep-phnucl-ex1 citation

Affiliations

first authorsco-authorsvia INSPIRE