HEP Phenomenology·hep-ph

Tue·Aug 18, 2026Tuesday·August 18, 2026

42 papers—28 primary·14 cross-listed

01
Observing Macroscopic Consequences of Electroweak Anomalies with Archival DELPHI Data
Jingyu Zhang🇺🇸 · Kyle Lee🇺🇸 · Ian Moult🇺🇸 · Yi Chen🇺🇸 · Yen-Jie Lee🇺🇸
In this Letter, we emphasize that asymmetries in charge flux produced in the decays of on-shell Z-bosons provide a macroscopic manifestation of electroweak anomalies in the Standard Model (SM). We propose that these can be cleanly observed using charge correlators, providing a new formulation of forward-backward asymmetry measurements that is particularly well suited for precision studies of hadronic decays. Using archival DELPHI data, we perform a first measurement of the one-point charge correlator of electromagnetic charge flux on hadrons, and cleanly observe the macroscopic imprint of the underlying anomaly. Our analysis illustrates the potential of charge correlators as precision electroweak observables, and motivates a renewed effort to resolve longstanding tensions in hadronic asymmetry measurements.
hep-phhep-ex1 citation
02
First Order Phase Transition Induced Graviton Bremsstrahlung: A Multi Peak Gravitational Wave Signature
Dipendu Bhandari🇮🇳 · Rajat Kumar Mandal🇮🇳 · Arunansu Sil🇮🇳
Gravitational waves (GWs) from first order phase transitions (FOPTs) are conventionally sourced by bubble collisions, sound waves, and plasma turbulence. We propose a novel microscopic GW source arising from graviton bremsstrahlung during the decay of the scalar field driving the FOPT. In the presence of Yukawa interactions with light fermions, the scalar decay is inevitably accompanied by graviton emission due to the universal coupling of gravity to the energy-momentum tensor. We show that these gravitons generate an additional stochastic GW background during the phase-transition epoch, complementing the conventional FOPT signal. The resulting GW spectrum can exhibit a characteristic multi-peaked structure. Unlike scenarios in which different GW components originate from distinct cosmological epochs, all contributions considered here emerge from the dynamics of the same FOPT, offering a unique probe of both its microscopic particle dynamics and macroscopic plasma evolution.
hep-phhep-th0 citations
03
Energy Correlators in $V + X$ as a Benchmark Observable for Precision QCD
Terry Generet🇬🇧 · Kyle Lee🇺🇸 · Ian Moult🇺🇸 · Rene Poncelet🇵🇱 · Xiaoyuan Zhang🇺🇸
We propose projected energy correlators measured on the recoiling QCD radiation of a $Z / γ$ as a benchmark observable for precision QCD at the LHC. Using the $Z / γ$ as a hard scale prevents the need for a jet algorithm, simplifying both the perturbative and non-perturbative corrections. We develop a framework to combine state-of-the-art fixed-order amplitudes, high order resummation, and universal non-perturbative matrix elements. Our approach is based on numerically computed inclusive hard functions, allowing flexibility in the process and the inclusion of realistic experimental cuts. We perform detailed numerical studies of the projected energy correlators at next-to-leading order + next-to-next-to-leading logarithm (NLO+NNLL) to verify the stability of our setup. We present numerical results at NLO+NNLL, which are the first complete matched predictions for energy correlators at the LHC at this order. We discuss the prospects for extensions to higher orders, outlining a path to NNLO calculations of energy correlators at the LHC.
hep-phhep-exnucl-th1 citation
04
Radiative corrections to neutron $β$ decay with explicit $Δ (1232)$ degrees of freedom
Lemonia Gialidi🇳🇱 · Emanuele Mereghetti🇺🇸 · Jordy de Vries🇳🇱
We study electromagnetic radiative corrections to neutron $β$ decay within chiral perturbation theory extended to include the $Δ (1232)$ resonance as an explicit degree of freedom. Building on a previous analysis performed in the $Δ$ -less theory, we identify and compute additional loop contributions with intermediate $Δ$ states at leading and next-to-leading order in the small-scale expansion, and match the results to the pionless effective field theory. We find that the electromagnetic shift in the axial coupling is reduced by approximately a factor of two compared to the $Δ$ -less result. The correction remains at the percent level and is phenomenologically significant for the comparison between experimental extractions and lattice-QCD determinations of the nucleon axial charge. We also obtain a new $Δ$ -induced contribution to the weak magnetism term, which is an order of magnitude smaller than the pion-loop result and negligible for upcoming experiments.
hep-phhep-latnucl-th1 citation
05
Leading order quark-antiquark-W-boson vertex in the presence of a magnetic field
Alejandro Ayala🇲🇽 · Alejandro Lopez🇧🇷 · Ana Julia Mizher🇧🇷 · Manuel Emiliano Monreal Cancino🇲🇽 · Norberto Scoccola🇦🇷
We compute the leading order modification to the quark-antiquark- $W$ -boson vertex in the presence of a constant and uniform magnetic field, specifically for the case where the quark and antiquark are the $u$ and $d ˉ$ , respectively. We find the selection rules for transitions where the $u$ , $d ˉ$ , and $W$ -boson occupy arbitrary Landau levels. We show that, for the particular case where the initial particles each occupy the lowest Landau level, the $W^{+}$ is also produced in the lowest Landau level with a single polarization aligned with the magnetic field. We also illustrate the general findings by computing the case of transitions between low lying Landau levels and show the correspondence between the polarization vectors for the $W$ -boson and the polarization states for the quark and the antiquark.
hep-phhep-exhep-th0 citations
06
Uncovering Hidden Leptonic Correlations with Flow Matching and Autoencoders
Haruto Kitagawa🇯🇵 · Satsuki Nishimura🇯🇵 · Hajime Otsuka🇯🇵
We perform a global search for values of the Yukawa matrices and Majorana masses in the Type-I seesaw mechanism. Using flow matching, which is a generative artificial intelligence (generative AI) method, we generate a broad set of solutions reproducing the experimentally measured values of the neutrino mass-squared differences and the mixing angles. Then, a machine learning method known as an autoencoder is applied to uncover non-trivial correlations among physical quantities in the lepton sector. Our analysis reveals new non-linear relations involving neutrino masses and CP phases. These findings may contribute to elucidating the origins of the mass hierarchies and mixing patterns among generation structure.
hep-phcs.LGhep-th0 citations
07
Sensitivity to Single Vector-Like Bottom Quark Production at 3 TeV CLIC
R. Benbrik🇲🇦 · M. Berrouj🇲🇦 · M. Boukidi🇵🇱 · M. Ech-chaouy🇲🇦 · K. Kahime🇲🇦 · K. Salime🇲🇦
We study the sensitivity of the Compact Linear Collider at $s = 3 TeV$ to the single electroweak production of a vector-like bottom quark in a type-II Two-Higgs-Doublet Model extended by vector-like quarks. We consider the process $e^{+} e^{-} \to B b ˉ + B ˉ b$ , followed by $B \to ϕ b$ with $ϕ = H, A$ and $ϕ \to t t ˉ$ . We focus on the semileptonic final state with one charged lepton, missing transverse momentum, four $b$ -tagged jets, and two light jets. This channel directly probes the interplay between the extended quark and Higgs sectors. After applying theoretical constraints, electroweak precision constraints, Higgs-sector bounds, and current collider limits, we perform detector-level cut-based and multivariate analyses. The cut-based analysis remains below discovery sensitivity at $5 ab^{- 1}$ , while a multilayer perceptron and an XGBoost classifier provide substantially improved signal-background separation. For viable scenarios with $m_{B} ≃ 1.3$ -- $1.5 TeV$ , the expected significance remains above $5 σ$ even for a $15%$ uncertainty on the background normalization.
hep-ph1 citation
08
The Higgs boson decay $h \to b s$ in the Generational Three-Higgs-Doublet Model
Hao-Ran Ma🇨🇳 · Ti-Bin Hou🇨🇳 · Jin-Lei Yang🇨🇳 · Tai-Fu Feng🇨🇳
The Generational Three-Higgs-Doublet Model (G3HDM) extends the Standard Model (SM) by three Higgs doublets, which couple separately to different generations of quarks and charged leptons, and consequently make significant contributions to the neutral flavor-changing processes. Considering the latest experimental constraints on $125 GeV$ Higgs signals, electroweak precision observables, neutral-meson mixing, and the rare decay processes $B \to X_{s} γ$ and $B_{s}^{0} \to μ^{+} μ^{-}$ , we perform a systematic analysis of the processes $h \to b s$ predicted in the G3HDM. This process is strongly suppressed by the loop factor in the SM, hence any observation of $h \to b s$ in the near future provides a sensitive probe of physics beyond the SM. Finally, the constraints on the parameter space and the experimental testability of G3HDM through observation $h \to b s$ are presented.
hep-ph0 citations
09
Spin-dependent polarizabilities of heavy vector mesons
Hao Dang🇨🇳 · Liang-Zhen Wen🇨🇳 · Yan-Ke Chen🇨🇳 · Shi-Lin Zhu🇨🇳
We investigate the spin-dependent electromagnetic polarizabilities of the heavy vector mesons $D^*$ and $B^*$ in heavy meson chiral perturbation theory up to $\mathcal O(p^3)$. Using a twelve-element tensor basis for the real-photon Compton scattering on a spin-1 target, we determine two scalar, four vector and six tensor polarizabilities. We take the charm- and bottom-sector axial couplings from the measured $D^*$ width and lattice-QCD calculations, respectively, and estimate the magnetic couplings in the nonrelativistic constituent-quark model. In the charm sector, the proximity of the charged $D\pi$ thresholds generates strongly nonanalytic $P\phi$-loop contributions, producing large real contributions to several $\bar D^{*0}$ polarizabilities and sizable imaginary parts for $D^{*-}$, whose charged $D\pi$ channel is open. The $E1E1$-type polarizabilities are enhanced much more strongly than their $M1M1$-type counterparts, consistent with the velocity suppression of the pion-cloud magnetic coupling. No analogous enhancement occurs for $B^*$: the Born terms govern the magnetic polarizabilities, and the anomaly poles dominate the vector polarizabilities that receive no Born contribution. These results resolve the spin dependence of the $D\pi$ threshold effect and provide benchmarks for future lattice-QCD studies.
hep-phhep-latnucl-th0 citations
10
Dark Charge Conjugation and Complementary Constraints from $D^{0}$ Mixing and Rare Decays with Massless Dark Photons
X. Zhong🇨🇳 · X. Q. Shen🇨🇳
We investigate how dark charge conjugation organizes rare $D^{0}$ decays involving a massless dark photon and how these decays complement neutral charm mixing in constraining a common flavor changing interaction. Within a simplified framework with a real pseudoscalar mediator, $D^{0} \to γ_{D} γ_{D}$ probes the portal that preserves $C_{D}$ , whereas $D^{0} \to γ γ_{D}$ probes the portal associated with $C_{D}$ breaking. Because the two decay channels and $D^{0}$ mixing share the same flavor normalization and mediator propagator, the flavor dependence can be eliminated analytically, converting the mixing constraint into a direct upper bound on the invisible decay rate. Combining current constraints from mixing, invisible decay, and the single dark photon channel, we identify a transition between regions dominated by mixing and regions dominated by invisible decay in mediator parameter space. The single dark photon search then yields conditional upper limits on the portal associated with $C_{D}$ breaking once the flavor normalization is fixed at its maximal value allowed by mixing and invisible decay. These results demonstrate a symmetry resolved complementarity between neutral meson mixing and rare charm decays in probing flavor changing interactions with a massless dark sector.
hep-phhep-ex0 citations
11
Revisiting In-Medium QCD Effects on Spin-Polarized Strange Quark Stars
Manas Lohani🇮🇳 · Yogesh Kumar🇮🇳 · Poonam Jain🇮🇳 · Om Prakash🇮🇳 · Sanjay Tyagi🇮🇳 · Vinod Kumar🇮🇳 · T. A. Nahool🇪🇬
We investigate the properties of exotic Strange Quark Matter with spin polarization and the complex configuration of Strange Quark Stars using a phenomenological MIT Bag Model, enhanced by incorporating a QCD informed running strange quark mass dependent on the chemical potential. The effective mass using quasiparticle approach is utilized to understand the framework of SQM. The resulting Equation of State is constructed for two distinct parameter sets, yielding an energy per baryon below the iron limit for stable configurations and thus supporting the Bodmer Witten Terazawa hypothesis that SQM could be the actual ground state of exotic matter. This framework is then used to address the Tolman Oppenheimer Volkoff equations to study the effect of spin polarization on stellar properties. The model predicts that the maximum stellar mass increases with the degree of spin polarization, a result that diverges from previous constant mass models. Furthermore, the model predictions for mass, radius, and surface redshift are in excellent agreement with observational constraints for the compact object Vela X one. This agreement validates our theoretical approach and strengthens the candidacy of Vela X one as a Strange Quark Star. Overall, the model results highlight the importance of in medium QCD effects in describing dense matter.
hep-phActa Phys.Polon.B(2026)·0 citations
12
Exploring charmonia $η_{c} (6 S, 7 S)$ in the $Λ_{c}^{+} Λ ˉ_{c}^{-}$ invariant mass spectrum of $B^{0} \to K_{S}^{0} Λ_{c}^{+} Λ ˉ_{c}^{-}$
Cheng-Xi Liu🇨🇳 · Jun-Zhang Wang🇨🇳 · Xiang Liu🇨🇳
We analyze the $B^{0} \to K_{S}^{0} Λ_{c}^{+} Λ ˉ_{c}^{-}$ decay recently observed by the LHCb Collaboration. The $Λ_{c}^{+} Λ ˉ_{c}^{-}$ invariant-mass spectrum exhibits an accumulation near 4.63~GeV, which we investigate together with the accompanying $Λ_{c}^{+} K_{S}^{0}$ spectrum constrained by the known $Ξ_{c} (2923)$ and $Ξ_{c} (2939)$ states. Our amplitude model includes a nonresonant term, the two established $Ξ_{c}$ contributions, and high-lying charmonium states in the $Λ_{c}^{+} Λ ˉ_{c}^{-}$ channel. Guided by screened Godfrey--Isgur and quark-pair-creation calculations, we test the 4.63~GeV enhancement with a fixed $η_{c} (6 S)$ amplitude at $(4629.00, 24.20)$ ~MeV, {which improves the description of the 4.63~GeV region}, and examine a fixed $η_{c} (7 S)$ contribution at $(4718.84, 22.84)$ ~MeV, which improves the higher-mass region of the spectrum. We also evaluate the $η_{c} (n S) \to Λ_{c}^{+} Λ ˉ_{c}^{-}$ baryonic decays via a hadron-loop mechanism and estimate the $B^{0} \to K_{S}^{0} η_{c} (n S)$ production in naive factorization. Within the narrow width approximation, the fit yields a $B (B^{0} \to K_{S}^{0} η_{c} (6 S)) B (η_{c} (6 S) \to Λ_{c}^{+} Λ ˉ_{c}^{-})$ of about $6.2 \times 1 0^{- 6}$ , while the factorization and hadron-loop calculations give rates roughly one to three orders of magnitude lower than the above fitted ratio. These results highlight the need for more precise data and a full amplitude analysis to determine the line shapes and clarify the nature of the higher-mass contribution.
hep-phhep-ex0 citations
13
Probing the ALP--Photon--Dark Photon Interaction through the Mono-Photon plus Missing-Energy Signature at a Muon Collider
Chong-Xing Yue🇨🇳 · Yang-Yang Bu🇨🇳 · Xin-Yang Li🇨🇳 · Feng-Xia Tang🇨🇳
The dark axion portal provides a well-motivated framework for new physics beyond the Standard Model (SM), in which an axion-like particle (ALP) couples simultaneously to a photon and a dark photon, leading to distinctive collider signatures. In this work, we investigate the sensitivity to the $a$ -- $γ$ -- $γ^{'}$ interaction via the mono-photon channel arising from $μ^{+} μ^{-} \to a γ^{'}$ with $a \to γ γ^{'}$ at the $1.5 TeV$ muon collider with an integrated luminosity of $L = 500 fb^{- 1}$ for the polarized and unpolarized beam configurations, $P (μ^{+}, μ^{-}) = (- 100%, + 100%)$ and $P (μ^{+}, μ^{-}) = (0, 0)$ , using detector-level simulation. The signal is characterized by a single energetic photon accompanied by missing energy as the dark photons escape detection. The projected sensitivity reaches the $O (1 0^{- 5}) GeV^{- 1}$ level for ALP masses in the range $1 GeV \leq m_{a} \leq 1200 GeV$ for $P (μ^{+}, μ^{-}) = (- 100%, + 100%)$ , while for $P (μ^{+}, μ^{-}) = (0, 0)$ the projected sensitivity reaches the $O (1 0^{- 4}) GeV^{- 1}$ level for the same ALP mass range. These results demonstrate that the mono-photon signature at a muon collider provides a sensitive probe of the $a$ -- $γ$ -- $γ^{'}$ interaction over a wide mass range.
hep-ph0 citations
14
Probing 5.49 MeV Solar Axions at Xenon Experiments
Ruofei Feng🇨🇳 · Shao-Feng Ge🇨🇳 · Oleg Titov🇨🇳 · Yongchao Zhang🇨🇳
The monochromatic 5.49 MeV solar axions induced by the isovector coupling $g_{3 a N}$ can be searched for at the dark matter direct detection experiments. In this paper we estimate the prospects of the relevant axion couplings for axion mass $m_{a} <$ 1 MeV with xenon targets. Given the axion-electron coupling $g_{a e}$ , the signal is dominated by the axion-induced $e^{+} e^{-}$ pair production whose cross section is largely enhanced when the axion mass approaches twice of the electron mass. Furthermore, the cross section depends on the atomic number squared $Z^{2}$ . This allows the next-generation xenon experiments to surpass the current Borexino constraints and provide sensitivities competitive with those of the large neutrino detectors such as JUNO and Hyper-Kamiokande. With an exposure of 200 and 1000 ton $\cdot$ yr, the couplings $∣ g_{3 a N} g_{a e} ∣$ can be probed down to $1.59 \times 1 0^{- 14}$ and $7.12 \times 1 0^{- 15}$ at 90% C.L., respectively. If the axion couples to photons, the projected sensitivities on $∣ g_{3 a N} g_{aγ} ∣$ can touch down to $6.76 \times 1 0^{- 12}$ GeV $^{- 1}$ and $3.02 \times 1 0^{- 12}$ GeV $^{- 1}$ , respectively.
hep-phhep-ex0 citations
15
Estimation of the cumulant $b_{4}$ and sextic self-coupling of the QCD axion at finite temperature and density
Xinguang Li🇨🇳 · Zhao Zhang🇨🇳
The sixth-order cumulant $b_{4}$ of the QCD topological charge distribution and the axion's sextic self-coupling at finite temperature $T$ and baryon chemical potential $μ$ are calculated within the two-flavor quark-meson (QM) model without and with the Polyakov-loop dynamics. The $b_{4}$ in the vacuum falls within the range predicted by lattice SU(3) pure-gauge simulations, and at large $T$ and/or $μ$ , it tends to a constant predicted by the dilute instanton gas approximation. Both $b_{4}$ and the axion's sextic self-coupling diverge at the QCD critical point and flip sign across the phase transition. The convergence of the fourth- and sixth-order Taylor expansions of the free energy as a function of the $θ$ parameter is investigated via comparison with the full potential at the mean-field level.
hep-ph0 citations
16
Universality and Kinematic Dependence of Hadronization Effects in DIS Global Event Shapes
Radja Boughezal🇺🇸 · Haotian Cao🇺🇸 · Zhong-Bo Kang🇺🇸 · Xiaohui Liu🇨🇳 · Sonny Mantry🇺🇸 · Frank Petriello🇺🇸
We propose a unified framework for a combined global analysis to constrain leading hadronization effects across the 1-Jettiness class of global event shapes for Deep Inelastic Scattering (DIS). We show that for the subclass of jet-based event shapes where the leading jet direction is determined dynamically event-by-event, the leading hadronization effects can acquire a non-trivial dependence on the hard scattering kinematics. However, this dependence is explicitly calculable, allowing for universality of leading hadronization effects in the 1-Jettiness class. The non-trivial kinematic dependence provides an independent lever arm for simultaneously constraining hadronization effects in the jet-based and DIS thrust event shapes. This universality, combined with the kinematic lever arm, could allow for including the typically ignored peak region, where hadronization effects are most severe, in precision extractions of the strong coupling. We demonstrate the need for such a unified treatment of hadronization effects through comparisons of theoretical predictions with simulation data.
hep-phnucl-th1 citation
17
Photon Fragmentation Functions in LHAPDF: Existing Sets and a Pythia-Based Extraction
Alexander Puck Neuwirth🇮🇹
Prompt-photon predictions with experimentally relevant isolation criteria retain a residual dependence on parton-to-photon fragmentation functions, whose phenomenological uncertainties remain only weakly constrained. We present a pragmatic study of photon fragmentation functions extracted from Pythia parton-shower events and stored in LHAPDF grids. We briefly review the role of photon fragmentation in perturbative QCD and then construct shower-level estimates of the flavour-dependent functions $D_{γ / i}^{PS} (z, μ_{D})$ as functions of the photon momentum fraction $z$ and fragmentation scale $μ_{D}$ . The extracted distributions show the expected qualitative hierarchy between quark and gluon channels and an increasing fragmentation contribution with scale. In parallel, we convert the commonly used BFG, GRV, and GDRG parameterizations into LHAPDF grids and study their interpolation. We find that the default logcubic interpolation in LHAPDF reproduces the non-trivial $z$ - and scale-dependence of the tabulated fragmentation functions more faithfully than the linear interpolation commonly used in legacy implementations. We also define a simple collider-oriented envelope set, based on the BFG and GRV families. These results provide a portable baseline for future phenomenological studies and for more systematic extractions of photon fragmentation functions.
hep-ph0 citations
18
Functional anatomy of Pythia-Herwig differences with Kolmogorov-Arnold networks
Arghya Chattopadhyay🇺🇸
Differences between high-energy event generators can arise at several stages of the collision simulation, from the hard scattering through parton showering and hadronization to the final event. These differences are usually summarized using observable distributions or global classifier scores. While these quantify the disagreement, they do not reveal which observable-level structures carry it or whether those structures persist through different stages of event generation. In this work, we formulate this problem as a staged functional analysis of generator-model differences. Following the same hard dijet events through Pythia and Herwig at shower-only, hadronized, and full-generator levels, we use an additive Kolmogorov-Arnold network (KAN) representation of the classifier-derived log density ratio to decompose the learned discrepancy into explicit one-dimensional observable responses that can be isolated, recomposed, and transported between generator stages. Within the same eight-observable jet representation, the Pythia-Herwig difference is driven mainly by multiplicity at shower level, shifts toward jet mass and shape after hadronization, and develops a mixed shape-multiplicity driven structure in the full-generator configuration. Transporting the individual shower-level functional components downstream shows that shower-level multiplicity information can retain its reweighting power, whereas the corresponding shape responses need not do so even though shape becomes important again at later stages. The jet-mass factors, meanwhile, are limited by poor statistical support. This KAN-based framework therefore provides a functional anatomy of generator-model dependence, exposing both persistent structures and support failures that are hidden inside a single global classifier-derived reweighting function.
hep-phcs.LG0 citations
19
Probing T and CP Violation at DUNE and T2HK
Sabya Sachi Chatterjee🇩🇪 · Sudhanwa Patra🇮🇳 · Thomas Schwetz🇩🇪 · Kiran Sharma🇩🇪
We study the sensitivity of the DUNE and T2HK long-baseline experiments to time reversal (T) violation in neutrino oscillations. Rather than the conventional approach of exchanging initial and final neutrino flavors, we search for T violation through the $L$ -dependence of the $ν_{μ} \to ν_{e}$ transition probability at fixed neutrino energy using neutrino data only. Within the standard three-flavour framework, we show that the DUNE and T2HK together can establish the presence of an $L$ -odd component in the oscillation probability at up to $\sim 4 σ$ significance, with the optimal sensitivity in the energy range $E_{ν} \in [0.68, 0.92]$ GeV. The second oscillation maximum of DUNE plays a crucial role in this analysis. We further show that DUNE is more sensitive to T violation that is running in neutrino-only mode, whereas T2HK provides better sensitivity in the conventional neutrino versus anti-neutrino comparison, making the two experiments complementary to each other in search of the CP phase $δ_{CP}$ .
hep-phhep-ex0 citations
20
Assessing Parameter Redundancy in Transformers for Jet Tagging
Huitong Cheng🇨🇳 · Yabo Dong🇨🇳 · Jun Fan🇨🇳 · Kun Wang🇨🇳 · Haijun Yang🇨🇳 · Jingya Zhu🇨🇳 · Yifan Zhu
Transformer-based jet taggers, such as the Particle Transformer (ParT) and the More-Interaction Particle Transformer (MIParT), achieve excellent discrimination by exploiting correlations among jet constituents, but often require more trainable parameters than earlier deep-learning taggers. In this paper, we investigate whether comparable discriminating power can be achieved with substantially fewer parameters. We introduce an hourglass structure that replaces the feed-forward networks (FFNs) in the attention blocks while leaving the particle-interaction attention unchanged. We also introduce a lightweight particle-embedding layer to replace the original dense embedding network. Applying both modifications to ParT and MIParT yields the hourglass (HG) variants ParT-HG and MIParT-HG, respectively. We evaluate both models on benchmark datasets for top tagging and quark-gluon discrimination. Both variants retain comparable tagging performance, including background rejection at fixed signal efficiencies, while using only approximately 48% and 39.7% of the parameters of their respective baselines. On the larger JetClass dataset, accuracy and AUC decrease by less than 1%, and background rejection also decreases for several signal classes. Overall, our approach provides an alternative way to reduce the parameter count of Transformer jet taggers while largely retaining their tagging performance.
hep-phhep-ex0 citations
21
Unfolding the low-energy reactor neutrino flux from CE $ν$ NS data with a finite Dirac sum
Muping Chen🇯🇵 · Graciela Gelmini🇺🇸 · Danny Marfatia🇺🇸 · Koichiro Yasuda🇺🇸
We present a novel method to analyze coherent elastic neutrino--nucleus scattering (CE $ν$ NS) data to extract the reactor antineutrino spectrum below the inverse beta decay threshold of 1.8 MeV, where it remains unmeasured. Adapting halo-independent analysis techniques developed for direct dark matter detection, we show how to obtain a best-fit and a pointwise confidence band for the integrated neutrino flux, without assuming a parametric form or smoothness prior for the spectrum. In our approach, which follows from convex geometry arguments, the differential neutrino rate is written as a linear combination of Dirac delta functions -- a finite Dirac sum (FDS) -- with a maximum number of terms determined by the number of data points. We apply our ``FDS method'' to mock CE $ν$ NS data for a low-threshold Ge detector and compare it with Tikhonov-regularized unfolding.
hep-ph0 citations
22
Extending the Constituent Gluon Model to Heavy-Flavour Hybrids: A Unified Study of $c c ˉ g$ Mesons
Qi Huang🇨🇳 · Zhe-Tao Miu🇨🇳 · Rui Chen🇨🇳 · Xiao-Huang Hu🇨🇳 · Yue Tan🇨🇳
We investigate the mass spectra and two-body strong decay properties of ground charmonium hybrids within the framework of a constituent gluon model. Based on the assumption that non-perturbative QCD endows the gluon with an effective mass, we extend the chiral quark model by introducing a single new parameter, the constituent gluon mass $m_{g} = 450$ ~MeV, which is fixed from previous studies of light hybrids, while other parameters are taken directly from successful descriptions of ordinary meson spectra. We systematically compute the spectra for various quantum numbers and find good agreement with results from lattice QCD, potential models, and other approaches. The corresponding decay widths are also reasonable. For experimental searches, we recommend focusing on the exotic $1^{-+}$ and $2^{+-}$ states, which decay prominently into $D D ˉ_{1}$ and $D D ˉ_{2}^{*}$ channels, respectively. Among ordinary quantum numbers, the $0^{-+}$ , $2^{-+}$ , and $1^{+-}$ states with significant decays into orbitally excited charm mesons are also suggested. Our results provide a unified and consistent description of charmonium hybrids and offer clear guidance for future experimental identification.
hep-phhep-ex0 citations
23
Amplified Isospin Breaking from Coupled-Channel Dynamics Near Threshold
Xiang-Kun Dong🇩🇪 · Feng-Kun Guo🇨🇳 · Christoph Hanhart🇩🇪 · Teng Ji🇩🇪 · Ulf-G. Meißner🇩🇪
We identify the dynamical origin of amplified isospin breaking in near-threshold states. Using a pole-residue-based measure defined directly from the pole couplings, rather than from decay observables that are also affected by different final-state kinematics, we show that threshold proximity of the pole alone is insufficient: large isospin breaking requires a sizable interaction in the companion isospin channel. Applied to the $X (3872)$ , the observed large isospin breaking points to a nearby partner pole, $W_{c 1}$ , as predicted in previous studies. In addition, we find that the $W_{c 1}$ pole, which predominantly affects the line shapes near the charged threshold in the physical case, does not evolve into the pure $I = 1$ eigenstate in the isospin limit; instead, that eigenstate is continuously connected to a more distant shadow pole.
hep-phhep-exhep-lat0 citations
24
Cosmological Signatures of the Conformal and Non-Conformal Next-to-Minimal Two-Higgs-Doublet Model
Filip Gustavsson🇸🇪 · Roman Pasechnik🇸🇪 · Johan Rathsman🇸🇪
We investigate cosmological signatures of the next-to-minimal two-Higgs-doublet model (N2HDM) in both the classically scale-invariant, or conformal, realization and in the corresponding non-conformal theory. Using a one-loop finite-temperature effective potential, collider and flavour constraints implemented through ScannerS, HiggsBounds and HiggsSignals, and a modified on-shell counterterm prescription for the conformal model, we identify parameter regions with a first-order electroweak phase transition and potentially observable stochastic gravitational waves. We find that both conformal and non-conformal scenarios can produce sound-wave signals in the sensitivity range of future space-based interferometers, including LISA, while the electroweak transitions complete promptly ( $T_{n} ≃ T_{p}$ ), with pronounced supercooling below the critical temperature confined to the strongest transitions. The two scenarios nevertheless populate different regions of the scalar mass spectrum when the gravitational-wave signal is observable, suggesting that a future stochastic background measurement combined with collider information on the additional Higgs states could discriminate between the two realizations. We further study partonic Higgs-pair production, in the heavy-top approximation, and find that large deviations in the SM-like di-Higgs rate tend to occur away from the regions with the strongest gravitational-wave signals, while enhanced BSM Higgs-pair rates are mainly associated with the conformal model. The analysis highlights a complementary interplay between electroweak cosmology, scalar spectroscopy and Higgs self-interaction probes in extended Higgs sectors.
hep-ph0 citations
25
Rotation modified QCD equation of state across crossover at finite chemical potential
S. Ipsita Sahoo🇮🇳 · Sanjeebani Biswal🇮🇳 · Dipanwita Dutta🇮🇳 · Dipak Kumar Mishra🇮🇳
It is well-established that at low baryon chemical potential, the transition from the confined hadronic phase to the deconfined partonic phase is a smooth crossover rather than a first or second-order phase transition. We develop a thermodynamically consistent hybrid equation of state to study the effect of global rotation on the equation of state across the QCD crossover that interpolates the hadronic and partonic phases. The temperature dependence of normalized thermodynamic observables, such as entropy density ( $s / T^{3}$ ), pressure ( $P / T^{4}$ ), energy density ( $ε / T^{4}$ ), specific heat ( $C_{V} / T^{3}$ ), and the square of speed of sound ( $c_{s}^{2}$ ) in presence of rotation are investigated. The effect of non-zero chemical potential on thermodynamic quantities in presence of rotation is also studied. Our results show that increasing chemical potential enhances the thermodynamic quantities, whereas rotation suppresses them in the crossover region. Further, we investigate the effect of rotation on the conserved numbers susceptibilities and their correlations as a function of temperature. The susceptibilities and their correlations exhibit a systematic enhancement with increase in rotation in both the hadronic and partonic phases. These findings provide new insights into the interplay between rotation and QCD thermodynamics, which can have important implications for rapidly rotating strongly interacting matter produced in ultra-relativistic heavy-ion collisions.
hep-phnucl-exnucl-th0 citations
26
Two-loop tensor integral reduction for automated tools
Fabian Lange🇨🇭 · Max F. Zoller🇨🇭
In order to exploit the full potential of the LHC and future colliders, high-precision calculations of a very wide range of observables are crucial. Automated tools for next-to-next-to-leading order calculations of perturbative scattering amplitudes are therefore a highly desirable goal. So far, we have developed several major ingredients of such a tool in the OpenLoops framework. In our approach we split the calculation of scattering amplitudes into three components: loop momentum tensor integrals, the corresponding process-dependent tensor coefficients, and the interplay of $(D - 4)$ -dimensional parts of the integrand with divergences of the integrals. In these proceedings, we present a new recursive algorithm to reduce arbitrary two-loop tensor integrals to scalar integrals, which has been implemented into an efficient numerical tool. We also implemented a first version of the subsequent reduction to master integrals, which allows for a full validation of the algorithm. We present a first successful validation computation and discuss its dependence on the precision of the externally computed master integrals.
hep-ph0 citations
27
Exotics with gluonic excitations
Jozef J. Dudek🇺🇸
That the gluons of quantum chromodynamics self-interact with a strong coupling suggests the possibility of hadrons in which the gluonic field plays an essential role: Glueballs in which gluons stick together to produce a hadron in which no quarks are required, and hybrids in which an excited gluonic field couples to quarks. This chapter presents our contemporary theoretical understanding of such states, and the challenges associated with definitively identifying their presence within the experimental spectrum of hadrons.
hep-phhep-exhep-lat0 citations
28
Truncation of the Radial Ladder in Heavy Quarkonia
Wen-Xuan Zhang🇨🇳 · Si-Qiang Luo🇨🇳 · Xiang Liu🇨🇳
A fundamental open question in hadron spectroscopy is whether the radial excitation ladder of quarkonia truncates at a finite level---a possibility that would challenge the conventional quark-antiquark bound-state picture and offer decisive clues to the nonperturbative strong interaction. Taking advantage of the newly observed high-mass hadronic states, we address this issue by solving a screened Godfrey--Isgur Hamiltonian for charmonium and bottomonium using the Gaussian expansion method. The calculated spectra saturate at $4.74 GeV$ ( $c c ˉ$ ) and $11.67 GeV$ ( $b b ˉ$ ), while root-mean-square radii grow to $\sim 10 fm$ ---an order of magnitude above the confinement scale---where adjacent mass gaps drop below $10 MeV$ . Combining a threshold-based mass-gap criterion, defined by the onset of mass--radius decoupling, with additional diagnostics, we locate the operational upper radial limits at $n \approx 8$ -- $10$ for charmonium and $n \approx 12$ -- $13$ for bottomonium. Beyond these limits, the conventional $q q ˉ$ description ceases to apply. This work provides the first quantitative determination of these upper limits, and the proposed criterion is directly testable with forthcoming high-statistics data from BESIII, Belle II, and LHCb.
hep-ph0 citations
29
Unveiling Neutrino Nature with the Diffuse Supernova Background
Marco Manno🇮🇹 · Pablo Martínez-Miravé🇩🇰 · Irene Tamborra🇩🇰
The true nature of neutrinos--whether Dirac or Majorana--is a foundational, unresolved question. We demonstrate that the diffuse supernova neutrino background (DSNB) offers an untapped avenue to resolve this issue, provided neutrino magnetic moments are $≳ 1 0^{- 14} μ_{B}$ . The intense magnetic fields characteristic of a subset of collapsing massive stars can trigger resonant chirality flips. This flavor conversion physics alters DSNB fluxes in measurable ways that depend on the neutrino nature. A $20$ ~yr combined exposure at Hyper-Kamiokande loaded with gadolinium and JUNO can unravel this signature at $90%$ ( $99%$ ) confidence if the fraction of magnetorotational events exceeds $12%$ ( $20%$ ) of cosmic core collapses. This result holds independent of the mass ordering and establishes the DSNB as a critical gateway to unveiling the true identity of the neutrino.
↳ astro-ph.HEhep-ph0 citations
30
Applications of Flux Compactifications in F-Theory
Shing Yan Li🇺🇸
This thesis studies 4D F-theory compactifications with fluxes and their connection to particle physics, accompanied with a review of F-theory. First, we develop a general formalism for gauge symmetry breaking with fluxes. Vertical and remainder fluxes can be used to break a rigid gauge group, with the former simultaneously inducing chiral matter, even when the unbroken gauge group has no complex representations. We show that it is fairly likely to have three generations of chiral matter. We focus on the realization of the Standard Model gauge groups and chiral matter by breaking rigid $E_{7}, E_{6}$ gauge groups with an intermediate SU(5) gauge group, and provide examples of explicit constructions. Then, the phenomenological aspects of rigid $E_{7}$ models are studied in detail. We find that many other Standard-Model like features are naturally compatible with the $E_{7}$ models. For example, dimension-4 and dimension-5 proton decay are ubiquitously suppressed. Many of these features are due to the group-theoretic structure of $E_{7}$ and its F-theory geometry. In particular, a set of approximate global symmetries descends from the $E_{7}$ group, leading to exponential suppression of undesired couplings. These features suggest a new set of grand unified theories based on the $E_{7}$ group and its string theory construction. Finally, we study constructions of abelian gauge symmetries with exotic charges. By breaking a rigid nonabelian group to a U(1) gauge group using vertical flux, very large charges can arise in the massless or light spectrum. We give an explicit construction in 4D F-theory in which the vector-like matter carries charges as large as 657, which is much larger than the previously known bounds in F-theory. We heuristically argue that this result may provide an upper bound on charges for light fields under decoupled U(1) gauge groups in the F-theory landscape.
↳ hep-thhep-ph0 citations
31
Revisiting environmental effects on black hole quasibound-state spectra with relativistic perturbation theory
Yin-Da Guo🇨🇳 · Qi-Xuan Xu🇵🇹 · Richard Brito🇵🇹 · Enrico Cannizzaro🇵🇹
We present a relativistic framework for computing corrections to the eigenfrequency spectrum of a massive scalar field in perturbed black-hole spacetimes, including first-order shifts to decay rates and second-order mode-mixing effects. We also clarify the regime of validity of non-relativistic treatments and show that the accuracy of completeness-based descriptions is limited, highlighting the non-Hermitian nature of the spectrum. Using galactic halos and accretion disks as physically motivated perturbations, we benchmark the relativistic perturbative predictions to the eigenfrequency shifts against non-perturbative numerical solutions. We also present first-order relativistic eigenfrequency shifts induced by binary companions, whose potentially stronger impact on superradiant dynamics of massive scalar fields around spinning black holes motivates future dedicated analyses. Our results suggest that previous estimates of the termination of superradiance due to binary companions and disks should be revisited within a relativistic framework.
↳ gr-qchep-ph0 citations
32
Deep Earth imaging through neutrino and seismic tomography
Sanjib Kumar Agarwalla🇮🇳 · Arjun Datta🇮🇳 · Amol Dighe🇮🇳 · Vinod Kumar Gaur🇮🇳 · Anuj Kumar Upadhyay🇮🇳
This article is a report on the Deep Earth Neutrino + Seismic Imaging and TomographY (DENSITY 2026) mini-workshop, held on 23--24 February 2026 in the Department of Earth and Climate Science at the Indian Institute of Science Education and Research (IISER), Pune. The workshop was jointly organised by IISER Pune and the Institute of Physics (IOP), Bhubaneswar. Researchers from Earth Sciences and Neutrino Physics participated in the workshop to explore multipronged approaches for studying the deep interior of the Earth. Since the participants came from diverse scientific disciplines (seismology, geochemistry, mineral physics, and neutrino physics), the programme featured a series of overview talks introducing all participants to the basic concepts of each field and highlighting how these concepts may be applied to the study of the deep Earth.
↳ hep-exastro-ph.EPhep-phphysics.geo-phCURRENT SCIENCE, VOL. 131, NO. 1, 10 JULY…·0 citations
33
Prospects for Direct Detection of Ultralight Dark Matter candidates in deci-Hz Band with IndIGO-D
Md. Emanuel Hoque🇮🇳 · Andrew L. Miller🇨🇳 · Arunava Mukherjee🇮🇳
We investigate the sensitivity of IndIGO-D, a proposed space-based decihertz gravitational-wave interferometer, to different classes of ultralight dark matter. IndIGO-D will probe the $\sim 0.01$ -- $10 Hz$ frequency band between those accessible to current ground- and future space-based gravitational-wave interferometers, providing access to ultralight dark-matter masses beyond the reach of existing instruments. We consider two complementary signatures: interferometric displacements induced by coherently oscillating scalar (dilaton), vector (dark-photon, $U (1)_{B}$ and $U (1)_{B - L}$ gauge groups), and tensor fields with masses $m_{DM} \sim 1 0^{- 17}$ -- $1 0^{- 14} eV$ ; and changes in laser polarization induced by pseudoscalar axion dark matter at higher masses, around $m_{a} \sim 1 0^{- 12} eV$ . For the dilatons, dark photons and tensors, we compute the expected sensitivities using two pipelines -- cross-correlation and BSD excess-power -- assuming L-shaped and triangular interferometer layouts and three representative noise power spectral densities (S1, S2, S3), each for two years of continuous observation. We find that the projected sensitivities agree to within a factor of order unity across the search pipelines and interferometer geometries. In particular, we show that IndIGO-D could open previously unconstrained coupling parameter space for vector and tensor dark matter across $m_{DM} \sim 1 0^{- 16}$ -- $1 0^{- 14} eV$ , bridging the sensitivity of space- and ground-based experiments. For axion dark matter, we demonstrate that a complementary detection for laser light polarization shifts, limited primarily by photon shot noise, could probe the axion-photon coupling $g_{aγ}$ at masses around $m_{a} \sim 1 0^{- 12} eV$ at a level potentially better than that of other future experiments without degrading sensitivity to gravitational waves.
↳ astro-ph.COgr-qchep-exhep-ph+10 citations
34
General Lindblad equation for quarkonium evolution in a quark-gluon plasma
Aoumeur Daddi Hammou🇫🇷 · Jean-Paul Blaizot🇫🇷 · Pol Bernard Gossiaux🇫🇷 · Thierry Gousset🇫🇷
Accurate modelling and understanding of quarkonium production in ultrarelativistic heavy ion collisions requires a formalism that preserves the quantum properties of microscopic $Q ˉ Q$ systems while treating the interaction of such pairs with the quark-gluon plasma (QGP). The open quantum system approach has recently emerged as one of the most fruitful schemes to meet such requirements. However, the quantum master equations obtained so far in this context are derived assuming a strict ordering between the QGP temperature $T$ and the $Q ˉ Q$ energy gaps ( $Δ E$ ) of the quarkonia bound states. This limits their predictive power since, as the QGP expands and cools down, the system traverse all regimes between the quantum Brownian motion (QBM) regime for $T ≳ Δ E$ to the quantum optical (QO) regime for $Δ E ≳ T$ . In this paper, we derive and present a more general non-abelian quantum master equation of the Lindblad type, which does not suffer from these limitations and thus allows to faithfully describe the quantum evolution of the $Q Q ˉ$ pairs during the whole QGP-evolution. We also provide some illustration of the key quantities governing this equation.
↳ nucl-thhep-phhep-thquant-ph1 citation
35
Exotic $B_{s}$ mesons in the continuum from a nonperturbatively-tuned heavy quark action
R. J. Hudspith🇺🇸 · Daniel Mohler🇩🇪 · M. Stolz🇩🇪
In this work we predict the masses and binding energies of two $B_{s}$ exotic-meson candidates using Lattice QCD, namely the $B_{s 0}^{*}$ and $B_{s 1}$ . We use a relativistic heavy-quark action for the valence b-quark in our simulations, tuned fully non-perturbatively by a neural network. This allows us to take the continuum limit and eliminates the largest systematic we attributed to our previous determination of these states using Lattice-NRQCD. This is the first Lattice QCD study to show that these states remain deeply bound in the continuum limit. We thoroughly benchmark our heavy-quark approach by reproducing the experimental values of the 1S hyperfine splittings of $B$ and $B_{s}$ mesons, as well as the mass splitting between the $B$ and $B_{s}$ mesons. Our final results yield binding energies with respect to the $B K$ and $B^{*} K$ thresholds of $- 65.9 (6.0) (3.0)_{Iso}$ MeV and $- 60.6 (6.6) (3.0)_{Iso} (1.0)_{GEVP}$ MeV for the $B_{s 0}^{*}$ and $B_{s 1}$ respectively.
↳ hep-lathep-ph0 citations
36
Addressing position anomalies in the Strong Gravitational Lensing System HS~0810+2554 through Dark Matter Subhalos
Yuanlin Gong🇨🇳 · Lei Wu🇨🇳 · Qiang Yuan🇨🇳 · Tengyuan Zhang🇩🇪
Self-bounded dark matter (DM) subhalos are predicted to populate galactic halos in great abundance in the Cold Dark Matter (CDM) scenario. These substructures can leave observable imprints in strong gravitational lensing and have shown the ability to account for flux-ratio and position anomalies in multiply imaged systems. In this paper, we utilize the DM subhalos to address the image position anomalies of the two radio quads of HS 0810+2554 observed with the Very Long Baseline Interferometry. We model the lens using an elliptical power-law macro-lens supplemented by a population of CDM subhalos from numerical simulations and perform a dual-source reconstruction to fit all eight radio images simultaneously. We find that subhalos below $1 0^{6} M_{⊙}$ induce astrometric shifts smaller than the measurement uncertainties, whereas more massive subhalos naturally generate the required milliarcsecond perturbations without significantly altering the global lens configuration. Including CDM subhalos improves the fit from $χ^{2} = 60.38$ for the pure macro-lens to $χ^{2} = 1.61$ . Our results show that the position anomalies of HS~0810+2554 can be explained within the CDM framework and do not by themselves necessarily require non-standard scenarios like fuzzy DM or angular complexity in the macro-lens. Instead, they provide a sharp and testable manifestation of the subhalo population predicted by CDM.
↳ astro-ph.COhep-ph0 citations
37
Perturbative solutions for the bumblebee field in a Schwarzschild background
Demetre Seturidze · Don Colladay
In this paper, we investigate the behavior of a vector field subject to a Lorentz-violating quartic potential on a fixed Schwarzschild background. We analyze the equilibrium configuration of the field and its linear perturbations. We show that the equilibrium solution and spherically symmetric perturbations are governed by a quadratic function whose properties determine their qualitative behavior. By requiring the background field to be real and finite, we derive bounds on the allowed parameters and identify critical cases in which the monopole perturbations become enhanced. We further derive asymptotic expressions for multipole perturbations near the event horizon and at spatial infinity.
↳ gr-qchep-phmath-phmath.MP0 citations
38
Origin and limits of intermediate-mass dilepton thermometry
Lipei Du🇺🇸
We identify the physical origin and limits of intermediate-mass dilepton thermometry in relativistic heavy-ion collisions. Using a controlled expanding-fireball framework with thermal dilepton rates, we show that the local inverse-slope parameter of the invariant-mass spectrum follows, to percent-level accuracy, the emission-weighted harmonic mean of the temperatures contributing to the spectrum. As the thermal-stage initial temperature increases, the temperatures sampled by the radiation shift upward with the overall thermal scale, causing their harmonic mean to track the initial temperature closely. This provides the physical basis for the strong inverse-slope--initial-temperature correlation, while the resulting mapping remains nonuniversal: changes that only rescale the amount of radiation leave it unchanged, whereas changes in the cooling history or source composition redistribute the radiation among different temperatures and modify the response. The mapping is nevertheless nearly linear over the temperature range studied here. Because different invariant-mass windows weight the emission history differently, source scenarios with the same inverse-slope parameter in $1 < M < 3 GeV$ develop different inverse slopes in harder mass windows. Intermediate-mass dilepton spectra therefore provide a quantitative but nonuniversal probe of the early thermal history, while measurements in multiple mass windows, when confronted with realistic calculations, can provide additional constraints on the thermal evolution and early electromagnetic source content.
↳ nucl-thhep-ph0 citations
39
Multipolar Neutrino Radiation in Binary Neutron Star Mergers: Angular Structure, Rotational Variability, and Implications for Electron Fraction
Kutay Arınç Çokluk🇹🇷 · Albino Perego🇮🇹 · Federico Maria Guercilena🇮🇹 · Kadri Yakut🇹🇷
The angular structure and temporal variability of neutrino emission from binary neutron star mergers are characterized using fully general-relativistic simulations with energy-integrated M1 neutrino transport across a representative set of equations of state, total masses, and mass ratios. The angle-dependent neutrino energy flux is extracted on a spherical surface outside the remnant and decomposed into spherical harmonics to quantify its multipolar content and evolution. Following the initial post-merger transient, the neutrino radiation flux approaches an axisymmetric configuration dominated by a strong quadrupolar component, producing persistent polar flux enhancement and equatorial suppression due to torus shadowing. The dipolar contribution remains subdominant, indicating the absence of sustained one-sided emission. The degree of anisotropy increases with mass asymmetry and for softer equations of state, reflecting the compactness and morphology of the remnant--disk system. Superimposed on this time-averaged geometry, coherent azimuthal modulations associated with the $m = 1$ mode are identified. Fourier analysis reveals a characteristic frequency of $\sim 0.6$ -- $0.7$ kHz, consistent with differential rotation in the remnant and inner disk layers, indicating a dynamical coupling between rotational structure and neutrino emission variability. Finally, we quantify how the same quadrupole-dominated radiation geometry induces a latitude-dependent equilibrium electron fraction. The polar material is driven close to the neutrino-equilibrium target, whereas equatorial material remains systematically more neutron-rich and below equilibrium.
↳ astro-ph.HEgr-qchep-ph0 citations
40
Quantum Stability of the Fuzzy Sphere Black Hole Horizon
Chong-Sun Chu🇹🇼
We establish the perturbative stability of the fuzzy-sphere black-hole horizon in the large- $N$ matrix quantum mechanics of \cite{Chu:2024qil}. Large- $N$ counting shows that the leading quantum correction to the fluctuation spectrum is the planar bosonic one-loop contribution, while higher-loop bosonic effects and the leading fermionic one-loop contribution are parametrically suppressed. The classical spectrum contains a tachyonic $(1, 2)$ mode and a marginal $(2, 3)$ mode; we show that both acquire positive quantum curvature and are stabilized. For the general spectrum, we find that a factorization structure of the Hessian controls the leading quantum curvature and renders it non-negative. Quantum effects dominate the stabilization of generic low-angular-momentum modes, whereas classical curvature dominates at high angular momentum. The two effects become comparable in the crossover regime $L \sim N$ , where both must be retained. Under smoothness and non-saturation assumptions supported by finite- $N$ numerical tests, positivity of the quantum fluctuation spectrum is thus established for sufficiently large but finite $N$ . This local curvature stability is compatible with non-perturbative monopole tunneling. Intriguingly, the same $L \sim N$ mesoscopic angular momentum range also dominates the tunneling process, suggesting a distinguished IR--UV crossover regime in the quantum dynamics of the black-hole horizon.
↳ hep-thgr-qchep-ph1 citation
41
The linear dilaton in cosmology and particle physics
Eugenio Megias🇪🇸 · Mariano Quiros🇪🇸
A warped extra dimension in a five-dimensional (5D) anti de Sitter (AdS) background was introduced in 1999 by Lisa Randall and Raman Sundrum to solve the gauge hierarchy problem in particle physics. As a bonus, a holographic interpretation in terms of four dimensional (4D) conformal field theories (CFT) was found. Interestingly enough, another 5D background, the linear dilaton (LD), was found to have a holographic interpretation in terms of Little String Theory. In this review we will show how a set of 5D backgrounds, parametrized in terms of a real parameter $ν$ , generalizes both theories and gives rise, in particular, to AdS for $ν = 0$ and to LD for $ν = 1$ . Furthermore, working in the 5D theory, we will consider applications of the LD background to: i) Particle Physics, so that the 5D Planck scale can be lowered to sub-Planckian values, ii) Brane World Cosmology (BWC), based on the appearance of an extra vacuum characterized by a 5D black hole. In all cases we find a gapped continuum for bulk propagating fields, which makes connection with unparticles. In the case of BWC we also point out on the existence of a pressureless holographic fluid which could play the role of dark matter (DM), with feeble (gravitational) interactions to the Standard Model (SM), decoupled from the thermal SM bath, and generated by a freeze-in mechanism after inflation. We also point out the additional possibility of identifying DM with a long-lived feebly interacting massive graviton, as an isolated resonance generated by radiative corrections to the continuum graviton propagator self-energy.
↳ hep-thastro-ph.COgr-qchep-ph0 citations
42
Quantum Simulation of QCD in Axial Gauge
Xiaojun Yao🇺🇸
We study quantum simulation of SU(3) non-Abelian gauge theory dynamically coupled with fundamental fermions in $3 + 1$ dimensions by employing the lattice Hamiltonian in axial gauge that avoids Gauss's law constraints. The temporal component of the gauge field is analytically solved in terms of independent field degrees of freedom and a lattice regulated Green's function. The axial gauge condition is trivially maintained in time evolution, even under Trotterization. The gauge field degrees of freedom are expressed in the local field basis and can be efficiently transformed into the canonical conjugate momentum basis by local quantum Fourier transforms. We prove the number of qubits needed for describing all states up to an energy $E$ with an accuracy $ϵ$ on a lattice of volume $V$ at bare coupling $g$ is bounded as $16 n_{A} V + 12 n_{f} V$ , where $n_{A} \approx lo g_{2} (\frac{64 E ^{'} V ^{4/3}}{π ^{2} ϵ} + \frac{32 2 g n _{f} E ^{' 1/2} V ^{7/6}}{3 π ^{3} ϵ ^{1/2}})$ is the number of qubits needed for each independent gauge field per site with a shifted energy $E^{'}$ , and $n_{f}$ denotes the number of fermion flavors. We then analyze a quantum algorithm for time evolution that is based on Trotterization, quantum Fourier transform, and Jordan-Wigner transformation, for which quantum circuits can be explicitly constructed under arbitrary gauge field truncation and digitization. We find the numbers of CNOT and single-qubit rotation gates both scale as $O (n_{A}^{4} V^{4/3}) + O (V^{5/3})$ per Trotter step for fixed $n_{f} \leq 6$ . We conclude that quantum resources needed for simulating real-time dynamics of lattice QCD scale polynomially with volume, energy, time, accuracy, and bare Hamiltonian parameters.
↳ hep-lathep-phhep-thnucl-th+13 citations

Affiliations

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