HEP Phenomenology·hep-ph

Thu·Jun 25, 2026Thursday·June 25, 2026

33 papers—27 primary·6 cross-listed

01
Probing Confining Dark Sectors with Cosmological Perturbations
Daven Wei Ren Ho🇺🇸 · Ameen Ismail🇺🇸 · Yuhsin Tsai🇺🇸
Dark matter may emerge as a composite state of a dark sector which confines in a strongly first-order phase transition (PT). To avoid structure formation constraints on warm dark matter, the dark PT must occur above the keV scale. We investigate the cosmological signatures of this scenario, focusing on a keV- to MeV-scale PT. The stochastic nature of bubble nucleation sources curvature perturbations that can be constrained by various cosmological observations. Composite dark matter inherits the isocurvature perturbations generated during the PT and sources large-scale curvature perturbations. In contrast to a PT that reheats into dark radiation, the slower redshifting of dark matter enhances the infrared tail of the curvature perturbation upon horizon entry. The PT-induced perturbations compete with the suppression of the matter power spectrum due to the free-streaming of composite dark matter. We place limits on the PT strength and temperature from cosmic microwave background anisotropies, the Lyman- $α$ forest, and other probes of the small-scale matter power spectrum. In a minimal scenario where the relic density is determined by the PT parameters, this provides a concrete example of a dark matter model that is testable via measurements of cosmological perturbations -- even in the absence of a sizable nongravitational coupling to the visible sector.
hep-phastro-ph.CO1 citation
02
Cosmological gravitational particle production in multifield inflation
Edward W. Kolb🇺🇸 · Sarunas Verner🇺🇸 · Jingyuan Wang🇺🇸
We study cosmological gravitational particle production (CGPP) of dark matter in two-field inflationary backgrounds with both flat and curved field-space geometries. As a concrete realization of broader multifield mechanisms, we adopt a Starobinsky+quadratic potential and construct benchmark scenarios that interpolate between the flat field-space limit and the sidetracked attractor on a hyperbolic field space, and we compute the production spectrum of a gravitationally coupled spectator scalar for both minimal ( $ξ = 0$ ) and conformal ( $ξ = 1/6$ ) coupling to the Ricci scalar. We show that negative field-space curvature can strongly enhance the post-inflationary oscillations of the Ricci scalar, leading to an enhancement of up to an order of magnitude in the CGPP number density relative to the flat field-space limit, particularly for minimal coupling. For the sidetracked attractor, this enhanced production competes with a reduced inflationary energy scale, leading to a nontrivial dependence of the relic abundance on model parameters. We derive the relic abundance as a function of spectator mass and reheating temperature, and identify the viable parameter space for each benchmark. The conformal case $ξ = 1/6$ , whose scalar mode equation is structurally analogous to that of a massive Dirac fermion, is much less constrained by isocurvature and provides a minimal scenario for purely gravitational dark matter production in multifield inflation.
hep-phastro-ph.COgr-qchep-th0 citations
03
Fermion mass relations in one-parameter modular models
Salvador Centelles Chuliá🇪🇸 · Xueqi Li🇺🇸 · Xiang-Gan Liu🇺🇸 · Omar Medina🇪🇸 · J. T. Penedo🇮🇹
Modular flavour symmetries provide a possible organizing principle for the Standard Model Yukawa sector, by replacing generic couplings with a potentially small number of modular forms controlled by a single complex modulus. We study the extreme limit of this idea: \acp{OPM}, in which each charged-fermion mass matrix is fixed by a single modular invariant contraction. We develop a systematic method to construct such models, showing that the \ac{OPM} requirement is already highly constraining at the level of possible fermion hierarchies. In a concrete realization, the charged-lepton and down-quark sectors are controlled by the common modulus, leading to exact mass relations at the flavour scale, \[ m_s^5 = 2\sqrt{2}\,m_d^3m_b^2, \qquad m_\mu^3 = \sqrt{2}\,m_e m_\tau^2, \qquad m_s^2m_\tau = \sqrt{2}\,m_e m_b^2. \] We show that, once renormalization-group evolution and selective supersymmetric threshold effects are included, these high-scale relations can be made compatible with low-energy charged-fermion data. Our results provide a working proof of principle for \acp{OPM} and point towards a possible route to the flavour puzzle through highly
hep-phhep-th2 citations
04
Gravitational ultra-relativistic freeze-out during general reheating
Mathieu Gross🇫🇷 · Stephen E. Henrich🇺🇸 · Fotis Koutroulis🇨🇳
We investigate ultrarelativistic freeze-out (UFO) in the context of generic reheating scenarios. While the standard WIMP dark matter paradigm has been extensively studied, UFO has so far only been analyzed within the specific reheating channel $ϕ \to f f ˉ$ . Unlike in the standard WIMP mechanism, where dark matter can only be diluted after freeze-out at $T_{FO} \sim m_{χ} / O (10)$ , UFO dark matter can undergo freeze-in like phases following the initial freeze-out, driven by the non-trivial temperature evolution. The exact temperature evolution then needs to be accounted for, as a change in the temperature scaling can modify the IR/UV nature of UFO, impacting the relic abundance. We first generalize UFO to an arbitrary temperature profile $T \sim a^{- ξ}$ , making explicit the UV and IR regimes for a thermally averaged cross section $⟨ σ v ⟩ \sim T^{n} / Λ^{n + 2}$ . Then, as a concrete example, we consider the minimal scenario in which gravitational particle production at the onset of reheating sources an initial radiation abundance, and show that this early hot bath changes the UFO parameter space. We refer to this effect as GUFO. Specializing to $n = 2$ , we find that matter-like reheating ( $V \sim ϕ^{2}$ ) accommodates dark matter masses up to $1 0^{7} GeV$ for $Λ ≲ 1 0^{9} GeV$ as thermalization becomes less stringent, while radiation-like reheating ( $V \sim ϕ^{4}$ ) is compatible with GUFO across all reheating channels only if gravitational processes are taken into account.
hep-phastro-ph.CO1 citation
05
Probing Scalar Non-Standard Neutrino Interactions using High-Energy Astrophysical Neutrinos
Ankur Verma🇺🇸 · Carlos A. Argüelles🇺🇸 · P. S. Bhupal Dev🇺🇸 · Bhaskar Dutta🇺🇸 · Ivan Martinez-Soler🇬🇧
Scalar non-standard interaction (SNSI) of neutrinos contributes as modifications to the neutrino mass matrix in the oscillation Hamiltonian and can induce a small active-sterile mass splitting due to the matter effect induced by the relic neutrino background via a Majorana-type interaction. This framework leads to pseudo-Dirac behavior of neutrinos, introducing rich phenomenology in neutrino oscillations, particularly for high-energy astrophysical neutrinos. We show that these hyperfine active-sterile splittings imprint themselves in two complementary ways on high-energy astrophysical neutrino flux, namely, in modifying the flavor composition and energy distribution. In this work, we perform both flavor and spectral analyses of the high-energy astrophysical neutrino flux to probe SNSI. We confront the predicted flavor ratios with current IceCube measurements and with the projected reach of next-generation detectors such as IceCube-Gen2. For the spectral analysis, we use the diffuse-flux ESTES (tracks) and cascade data sets, together with point-source spectral shape analysis based on a recent catalog of neutrino-bright sources. The regions excluded by the combined flavor and spectral analyses are translated into limits on the underlying SNSI parameters, namely, Yukawa couplings and scalar mass, providing new sensitivities on the SNSI parameter space for ultra-light mediators.
hep-ph1 citation
06
Nuclear Gluon Gravitational Form Factors and Neutron Skins at the Electron-Ion Collider
Lei Wang🇨🇳
Coherent quarkonium production at the Electron--Ion Collider can image the average small- $x$ gluon radius of nuclei, providing a reaction mechanism complementary to parity-violating electron scattering. We develop a calibrated radius-sum-rule framework that connects this gluonic radius to neutron skins and quantify the leading limitations from finite-dipole saturation, nuclear opacity, and instrumental resolution. The central result is that coherent $\Jpsi$ production contains sufficient shape information for a competitive neutron-skin program, but its precision is not limited by luminosity alone. It is instead controlled by the calibration of the nuclear small- $x$ gluon density, while the cleaner $\Ups$ channel remains statistically limited at early EIC luminosities. This framework identifies what an EIC neutron-skin measurement can robustly add to symmetry-energy studies and which theoretical and experimental controls are required before such a measurement can be interpreted as precision nuclear-structure information.
hep-ph1 citation
07
Halo-Independent Quantum Sensor Probes of Low-Velocity Dark Matter
Muping Chen🇯🇵 · Graciela B. Gelmini🇺🇸 · Volodymyr Takhistov🇯🇵 · Koichiro Yasuda🇺🇸
We present a halo-independent framework for sub-GeV dark matter (DM) direct detection using quantum sensors with sub-eV energy thresholds. Such detectors enable access to low DM velocities and may be sensitive to departures from the Standard Halo Model that are challenging to probe with conventional direct DM detection experiments. The method expresses the DM scattering event rate in terms of a detector and particle model-dependent response function, and a universal halo function common to all experiments to be determined from data. This allows the local DM velocity distribution to be constrained. As representative implementations, we consider TES (Al) and MKID (TiN)-like sensors and show that their differing material responses probe complementary regimes of the DM velocity distribution. Applying the framework to mock data derived from several benchmark local halo models, we demonstrate how the assumed halo function could be reconstructed. This framework demonstrates the potential of quantum sensors as a new avenue for mapping the local DM velocity distribution.
hep-phastro-ph.COhep-exquant-ph0 citations
08
A Solar-System Window for Hidden Stellar Companions
Karim Benakli🇫🇷
Could the closest stellar or substellar object to the Sun be not an ordinary star at parsec distance, but a hidden-brane companion at hundreds or thousands of astronomical units? We do not perform a new Solar-System dynamics analysis; instead we construct a phenomenological mass-distance map using an illustrative ephemeris tidal envelope calibrated to Planet-Nine-like constraints. A smooth dark matter halo cannot supply such an object: the local density contains only a sub-Pluto mass within 1000 AU. A nearby hidden-brane companion must therefore be a structured, gravitationally bound object rather than a typical halo draw. The illustrative envelope still allows Earth to sub-Saturn masses at 300-1000 AU, rising to Jovian mass near 2000 AU. In a simple QCD-scaled hidden sector with a confinement scale about ten times larger than ordinary QCD, the minimum hidden stellar mass overlaps the upper part of this window, providing a benchmark for a genuine hidden-sector star: bright in dark photons, electromagnetically dark to us, and visible only through gravity. We also derive an Earth-based source-strength proxy for brane-to-brane channels and show that, along the ephemeris envelope, it grows as the square of the companion distance: the largest received source scale comes from the most massive companion still allowed, not the nearest one. A probe sent to the companion's gravitational projection would reduce the ordinary source-receiver separation by two to three orders of magnitude relative to Earth-based operation. This is not a detection forecast; the excitation of KK modes, the compact-direction brane-to-brane transfer factor, and the detector response remain model-dependent.
hep-phastro-ph.COastro-ph.EPhep-th0 citations
09
Higgs Scattering and Entanglement in SMEFT
Hyun Min Lee🇰🇷 · Rojalin Padhan🇰🇷
We regard the weak isospin of the Higgs doublet as a qubit and classify the entanglement measures for the Higgs scattering in the Standard Model Effective Field Theories (SMEFT) and their Ultra-Violet complete models. We consider Higgs scattering in the unbroken phase for electroweak symmetry. Treating the final state as a momentum-isospin bipartite system, we obtain von Neumann and linear entropies to quantify momentum-isospin correlation. From the momentum reduced state, we calculate the concurrence, which measures the entanglement between the two isospins. Both quantities are set by the isospin singlet and triplet scattering amplitudes, and hence by the Wilson coefficients of the dimension-6 and dimension-8 Higgs operators. We find that the von Neumann entropy grows as a function of the total energy in SMEFT as compared to the SM case, but it undergoes a cancellation in the medium energy below the cut-off scale due to the interference effects between the dimension-4 and dimension-8 operators, in particular, when the effective interactions stem dominantly from a massive graviton. Assuming the dominance of dimension-8 operators, we find the conditions for entanglement suppression in the forward or backward scatterings or across all the kinematics. We also show the correlations between the entanglement suppression and the positivity bounds in the forward limit.
hep-ph1 citation
10
Weak decay of the positronium ion
Nishat Ul Sani🇵🇰 · M. Jamil Aslam🇵🇰 · Ishtiaq Ahmed🇵🇰
The positronium ion ( $Ps^{-}$ ), a coulombic three-body bound state of two electrons and a positron, predominantly decays via electron-positron annihilation into electromagnetic final states. While its radiative decay channels have been extensively studied, much less attention has been given to weak processes in this system. In this work, we investigate the rare decay $Ps^{-} \to e^{-} ν_{μ} ν ˉ_{μ}$ , obtained by replacing the photon in $Ps^{-} \to e^{-} γ$ with a virtual $Z$ boson. Treating the three-body process as an effective two-body transition, $Ps^{-} \to e^{-} Z^{*} (\to ν_{μ} ν ˉ_{μ})$ , we compute the decay rate by explicitly evaluating all spin configurations of the initial bound state and final particles. The result agrees with that obtained using the standard spin-summation formalism of quantum field theory. We find that the branching ratio is comparable to that of the weak decay of ortho-positronium, $o - Ps \to γ ν ν ˉ$ .
hep-phhep-exquant-phPRA(2026)·1 citation
11
Implementation of DIS at N $^{3}$ LO for PDF determination
Andrea Barontini🇮🇹 · Marco Bonvini🇮🇹 · Niccolò Laurenti🇮🇹
In this work we construct an accurate description of Deep-Inelastic Scattering (DIS) at third order in perturbative QCD that is valid at all energy scales. We do so by assembling massless and massive results in a variable flavour number scheme, performing a careful power counting of the various contributions. We also propose an improved approximation for the massive neutral-current DIS coefficient function at order $α_{s}^{3}$ , whose construction is validated against lower order results. These results are instrumental for state-of-the-art next-to-next-to-next-to-leading order fits of parton distribution functions.
hep-phhep-ex1 citation
12
Disentangling Dark Gauge Symmetries with Deep Learning on the Lund Jet Plane
Jinmian Li🇨🇳 · Junle Pei🇨🇳 · Rao Zhang🇨🇳
While dark sectors with new confining gauge symmetries are compelling candidates for resolving the dark matter mystery, discerning the underlying dark gauge group structure remains a significant phenomenological challenge. In this work, we systematically investigate the distinct radiation patterns of dark quarks and gluons by developing a novel Monte Carlo parton shower simulation framework applicable to arbitrary gauge groups. To handle generalized color topologies and the momentum recoil scheme, our algorithm constructs color dipoles using a group-theoretic tagging procedure. Furthermore, our simulation framework employs an exact three-body phase-space parameterization by analytically solving the cubic kinematic equation for each branching. This enables capturing full mass effects for both dark quarks and dark gluons, naturally yielding precise boundaries including mass-induced gaps and dead-cone thresholds. To decode these complex emission topologies, we utilize the Lund Jet Plane representation alongside a dedicated Neural Sorter Mamba Network. We demonstrate that our framework can successfully disentangle the perturbative footprints of different gauge symmetries. Finally, we show that our discrimination power remains robust against the unknown non-perturbative details of dark hadronization by maintaining high classification efficiencies even under stringent infrared $k_{T}$ cutoffs, and we explicitly quantify the impact of massive dark gauge bosons on the classification sensitivity.
hep-ph1 citation
13
SU(3)-flavor breaking as a structural probe of hidden-charm-strange $0^{--}$ tetraquarks in a color-octet basis
Bing-Dong Wan🇨🇳 · Jun-Hao Zhang🇨🇳 · Yan Zhang🇨🇳 · Ming-Yang Yuan🇨🇳
We study hidden-charm-strange tetraquark candidates with the exotic quantum number $J^{P C} = 0^{--}$ to test whether SU(3)-flavor breaking acts as a universal mass shift or as a structural probe of a fixed color-octet current basis. Using $[c ˉ c]_{8_{c}} \otimes [s ˉ s]_{8_{c}}$ -type and $[c ˉ s]_{8_{c}} \otimes [s ˉ c]_{8_{c}}$ -type color-octet currents within QCD sum rules, we keep the strange-quark mass and strange condensates explicitly in the operator product expansion through dimension eight so that the strange-sector response can be traced at fixed color and Dirac structure. The hidden-charm-strange system is treated as the primary phenomenological target, while the hidden-bottom-strange sector serves as a stability benchmark. The strange-sector spectrum remains ordered, but the induced charm-sector shifts are grouped rather than uniform, with relatively small shifts for the $[c ˉ c]_{8_{c}} \otimes [s ˉ s]_{8_{c}}$ configurations and substantially larger shifts for the $[c ˉ s]_{8_{c}} \otimes [s ˉ c]_{8_{c}}$ ones. The $[c ˉ s]_{8_{c}} \otimes [s ˉ c]_{8_{c}}$ solutions are shifted toward the $D_{s}^{*} D ˉ_{s 1}$ threshold region, with one overlapping this region within uncertainties and another showing the largest positive SU(3)-breaking shift. Taken together, these features indicate that hidden strangeness can serve as a useful discriminator of internal current structure in the exotic $0^{--}$ sector.
hep-ph1 citation
14
Quark Reggeization in QCD from the Wilson line formalism
Tolga Altinoluk🇵🇱 · Guillaume Beuf🇵🇱 · Jules Favrel🇵🇱 · Michael Fucilla🇵🇱
We establish a Wilson-line formulation of quark Reggeization in QCD. An interpolating operator for the Reggeized quark is identified in terms of semi-infinite Wilson lines, and its nonlinear rapidity evolution is derived. We provide strong evidence that this operator remains an eigenstate of the rapidity evolution up to next-to-leading logarithmic accuracy. Within the leading logarithmic accuracy, we explicitly recover the one-loop quark Regge trajectory. Our results provide a first-principles operator framework for quark Reggeization and pave the way for a systematic all-order description of high-energy QCD amplitudes with $t$ -channel quark exchange in terms of Wilson lines.
hep-phhep-th0 citations
15
Spin-dependent neutrino oscillations in torsion backgrounds: A quantum-field-theoretic analysis
Raoul Serao🇮🇹 · Giuseppe De Maria🇮🇹 · Simone Monda🇮🇹 · Aniello Quaranta🇮🇹 · Antonio Capolupo🇮🇹
We study neutrino mixing in a background with spacetime torsion within the quantum-field-theoretic formulation of flavor oscillations. Working in the Einstein--Cartan framework and neglecting curvature, we quantize Dirac fields in constant and linearly time-dependent axial-torsion backgrounds. A constant spatial torsion component lifts the degeneracy between the two spin orientations through spin-dependent effective masses and energies. In quantum field theory this splitting modifies not only the oscillation frequencies but also the amplitudes, because the Bogoliubov coefficients entering the flavor operators depend on spin. The effect is largest at low momentum when the torsion scale is comparable to the neutrino masses, while a dominant torsion term suppresses the relative mass splittings and can inhibit flavor conversion. We also discuss the induced spin dependence of the Dirac $C P$ asymmetry and of the condensate densities in the flavor vacuum. The results identify nonrelativistic neutrinos as the natural regime in which the difference between the field-theoretic and quantum-mechanical descriptions is most pronounced.
hep-ph0 citations
16
Decay constants of the $B_{c}$ mesons with vector and tensor currents
Eduard Costa i Reina🇩🇪 · Nico Gubernari🇩🇪 · Zachary Wüthrich🇩🇪
We calculate the decay constants of the lowest-lying $B_{c}$ mesons in the spin-parity channels $J^{P} = 0^{-}, 0^{+}, 1^{-}, 1^{+}$ , commonly referred to as the $B_{c}, B_{c 0}^{*}, B_{c}^{*}, B_{c 1}$ mesons, respectively. Within the framework of QCD sum rules, we consider the decay constants associated with both the (axial-)vector and (axial-)tensor interpolating currents. The decay constants with (axial-)vector currents have already been studied in the literature. We refine previous QCD sum rule results by including higher-order power corrections and performing a comprehensive uncertainty analysis. Furthermore, we provide the first determination of the (axial-)tensor decay constants of the $B_{c}^{*}$ and $B_{c 1}$ mesons. These new results will not only improve theoretical predictions for purely leptonic $B_{c}$ decays, but also strengthen unitarity constraints on $b \to c$ form factors, thereby improving the precision of predictions for $B ˉ \to D^{(*)} ℓ ν ˉ$ decays and the determination of $∣ V_{c b} ∣$ .
hep-ph1 citation
17
Dark Photons from Red Dwarfs
Stefan Vogl🇩🇪 · Xun-Jie Xu🇨🇳
Light dark photons can be produced in stellar systems and thus contribute to the stellar cooling rate. The additional cooling changes the evolution of the star and has an impact on various observable properties such as radius, photon luminosity or the emitted neutrino fluxes. This has been exploited before to derive limits based on observations of the Sun, horizontal branch stars and red giants. Given the wealth of astrophysical data collected in the last decade and the improvements in modeling stellar evolution it is interesting to investigate whether other stellar systems offer a complementary avenue towards testing dark photons. In this work, we study the effect on an alternative class of stars. We focus on the impact of dark photon induced cooling on red dwarfs, i.e. the lowest mass stars on the Hydrogen main sequence. Running simulations of the evolution of red dwarfs with dark photon cooling we determine the impact on the mass-radius relation. Combining our simulations with precise determination of mass and radius derived from observations of eclipsing binaries that have recently become available, we derive competitive limits which outperform the solar ones in a significant part of the parameter space.
hep-phastro-ph.COastro-ph.SR0 citations
18
Leptonic CP asymmetry and heavy neutrino searches in seesaw scenario
Arindam Das🇯🇵 · Wei Liu🇨🇳 · Supriya Senapati🇨🇳
We investigate the prospects for probing heavy Majorana neutrinos in the type-I seesaw framework at the 14 TeV LHC. In this scenario, the light-heavy neutrino mixing enables the production of heavy neutrinos in association with charged leptons, followed by decays into dilepton plus dijet final states. We perform a detector-level cut-based analysis of both same-sign (SS) and opposite-sign (OS) dilepton channels and investigate the sensitivity as a function of the ratio $R_{l l}$ of SS to OS events. We derive projected constraints on the light-heavy neutrino mixing as a function of the heavy-neutrino mass. For $R_{l l} ≃ 1$ , the sensitivity at $140 fb^{- 1}$ improves upon current LHC bounds by about one order of magnitude for $M_{N} ≃ 60 - 80 GeV$ , with a further order of magnitude improvement expected at the HL-LHC with $3 ab^{- 1}$ . The sensitivity decreases substantially for smaller $R_{l l}$ . We show that, for $50 GeV ≲ M_{N} ≲ 100 GeV$ , the collider reach is strongly correlated with $R_{l l}$ and the associated CP asymmetry, providing additional motivation for future measurements of $R_{l l}$ and heavy-neutrino oscillations at colliders.
hep-ph0 citations
19
Electroweak corrections to Higgs boson pair production: The quark channel
Marco Bonetti🇩🇪 · Gudrun Heinrich🇩🇪 · Philipp Rendler🇩🇪 · William J. Torres Bobadilla🇬🇧
We present the mixed QCD-electroweak corrections to Higgs boson pair production in the quark-antiquark channel. The virtual amplitudes are computed fully analytically using the method of differential equations. We determine the integration constants by matching our expressions to the large mass expansion limit of the canonical integrals. We implement the results in the POWHEG-BOX framework for phenomenological studies. The corrections are found to have a significant impact on the shapes of differential cross sections, reaching up to +10% for the invariant mass distribution of the Higgs boson pair near the production threshold. This channel has not been considered before in calculations of the next-to-leading order electroweak corrections to Higgs boson pair production.
hep-phhep-th0 citations
20
Complementary probes of Bilinear RPV SUSY models with a wino-like LSP via Neutrino Oscillation and LHC
Arghya Choudhury🇮🇳 · Arpita Mondal🇮🇳
In this work, we explore the bilinear R-parity violating Supersymmetry model's parameter space by performing a Markov Chain Monte Carlo scan with neutrino oscillation data, Higgs mass and its coupling strengths, and flavor observables such as $B$ -hadron decay branching ratios. From the allowed parameter space, we analyze the decay patterns of wino-like lighter charginos and lightest neutralinos and demonstrate how the branching ratios to different neutrino and charged lepton flavors depend on the neutrino mass hierarchy. Furthermore, we investigate the impact of current LHC bounds and projected future sensitivities from trilepton resonance searches on the allowed parameter space. We show that considering the branching ratio $Br (χ_{1}^{\pm} \to Z l^{\pm}; l = e, μ, τ) \sim$ 23\%, obtained at the best-fit point, the wino-like mass degenerate $χ_{1}^{\pm} / χ_{1}^{0}$ are excluded upto 565 GeV from LHC Run-II data. The projected exclusion reach with a similar branching ratio at High-Luminosity LHC (HL-LHC) is around 950 GeV. For a simplified scenario where $χ_{1}^{\pm} / χ_{1}^{0}$ decays via a $Z$ boson with branching ratios of 1\%, 50\%, and 100\%, wino masses can be excluded up to approximately $600 GeV$ , $1185 GeV$ , and $1350 GeV$ respectively. Our analysis shows that the HL-LHC can probe a significant portion of the 1 $σ$ allowed parameter space by neutrino oscillation measurements and other experimental constraints.
hep-ph1 citation
21
Forward Searches for Heavy Neutrinos and $Z^{'}$ Bosons at FCC-hh
ShivaSankar K.A.🇯🇵 · Souvik Das🇺🇸 · Arindam Das🇯🇵 · Sanjoy Mandal🇰🇷
The discovery of neutrino masses strongly motivates extensions of the Standard Model containing heavy neutral leptons and additional gauge interactions. We investigate the prospects for probing these states at the proposed Forward Physics Facility (FPF) of the 100 TeV Future Circular Collider (FCC-hh) within a broad class of anomaly-free chiral $U (1)$ gauge extensions. These models predict a new neutral gauge boson, $Z^{'}$ , together with right-handed neutrinos responsible for generating light neutrino masses through the seesaw mechanism. We study long-lived particle signatures arising from both heavy neutrinos and the $Z^{'}$ boson produced in the far-forward region. In particular, we analyze heavy neutrino production from meson decays, visible decays of long-lived $Z^{'}$ bosons produced through meson decays and proton bremsstrahlung, long-lived $Z^{'}$ bosons decaying into heavy-neutrino pairs, and prompt $Z^{'}$ decays yielding long-lived heavy neutrinos. The expected event rates are evaluated for the proposed FPF detector configurations, taking into account realistic detector geometry, decay probabilities, and visible final states. We derive projected sensitivities to the heavy neutrino mass and active-sterile mixing as well as to the $Z^{'}$ mass and gauge coupling for several representative $U (1)$ charge assignments. Our results demonstrate that the FPF at FCC-hh can substantially extend the discovery reach for light long-lived heavy neutrinos and light $Z^{'}$ bosons beyond existing and proposed experiments, providing a powerful and complementary probe of neutrino-mass models and hidden gauge sectors. https://github.com/SouvikPhD/RHN-Detection-with-FASER-2-
hep-ph1 citation
22
Factorization of the Energy-Energy Correlation in the two-jet limit in the massive case
Ugo Giuseppe Aglietti🇮🇹 · Giancarlo Ferrera🇮🇹 · Lorenzo Rossi🇮🇹
We consider non-logarithmic heavy-quark mass effects in the factorization and resummation of the Energy-Energy-Correlation (EEC) function, in the two-jet limit. We define a new, "partial" event fraction, restricted to the two-jet region and excluding the forward region, whose calculation at first order requires to consider real emission diagrams only, in $D = 4$ space-time dimensions (no need to consider virtual diagrams or take $D \neq = 4$ ). In order to determine explicitly the next-to-leading order coefficient function and the remainder function (both entering the standard resummation formula), we evaluate numerically the EEC spectrum at first-order in $α_{S}$ , finding good agreement with previous calculations. To have a smooth massless limit, a new, improved factorization scheme is proposed, in which the coefficient function also depends on the correlation angle $χ$ .
hep-phhep-ex0 citations
23
Lepton number violation at hadron colliders via pseudo-Dirac heavy neutral leptons
Stefan Antusch🇨🇭 · Jan Hajer🇵🇹 · Bruno M. S. Oliveira🇨🇭
Symmetry-protected low-scale seesaw models can account for the observed neutrino flavour oscillations without fine-tuning, while yielding collider-accessible signatures through pseudo-Dirac heavy neutral leptons (HNLs). Seesaw frameworks generically predict lepton number (LN) violation, which provides a powerful discovery channel. In symmetry-protected realisations, however, the amplitudes for LN violation are strongly suppressed by destructive interference between the contributions of the two quasi-degenerate HNLs within the usual QFT plane-wave treatment. We demonstrate that damped heavy neutrino-antineutrino oscillations significantly alleviate this suppression. We compare the sensitivities to pseudo-Dirac HNLs in both LN-blind and LN-violating channels at the LHC and future hadron colliders such as the FCC- $hh$ and the S $pp$ C. We find that, although searches for LN violation outperform their LN-blind counterparts, small mass splittings in the pseudo-Dirac HNL pair can drastically reduce the sensitivities in these channels. We further show that combining LN-blind and LN-violating searches can distinguish a pseudo-Dirac HNL pair from the double-Majorana limit in the intermediate regime where LN violation is observable but not yet saturated.
hep-phhep-exhep-th0 citations
24
New effect in neutrino spin oscillations in transversal matter currents with nonstandard interactions
Inna Kozlovskaya🇷🇺 · Alexander Studenikin🇷🇺
We perform a systematic study of a new phenomenon of neutrino spin and spin-flavor oscillations induced by transverse matter currents, based on the developed quantum treatment of the phenomenon. Both standard and nonstandard interactions of neutrinos with the external medium are taken into account. As an example, the oscillations in question are considered under the conditions of a binary neutron star merger model.
hep-ph0 citations
25
In-medium QCD splittings beyond the soft, large- $N_{c}$ and harmonic-oscillator approximations all at once
Marco Leitão🇫🇷 · José Guilherme Milhano🇵🇹 · Alba Soto-Ontoso🇪🇸
Nearly thirty years ago, Baier, Dokshitzer, Mueller, Peigné, Schiff, and Zakharov (BDMPS-Z) introduced a formalism to calculate the fully differential probability for a high-energy quark or gluon to radiate inside a finite-volume QCD plasma. We report on the first, complete numerical solution to the BDMPS-Z equations for in-medium QCD splittings. Our numerical routines are precise across phase-space, enabling a determination of the in-medium splitting functions that is significantly beyond the state-of-the-art, including finite-energy effects, subleading-color contributions, and a realistic model for parton-medium interactions. We quantify the uncertainties associated with standard approximations in the literature, revealing substantial deviations across phase-space. This work opens a path toward more precise calculations of jet observables and for powerful new constraints of medium parameters from high-energy heavy-ion collider data.
hep-phhep-exnucl-th3 citations
26
Impact of parity-violating deep-inelastic scattering on the weak mixing angle and high- $x$ parton distributions
R. M. Whitehill🇺🇸 · M. M. Dalton🇺🇸 · T. Liu🇨🇳 · W. Melnitchouk🇺🇸 · N. Sato🇺🇸
We discuss the impact of neutral current parity-violating deep-inelastic scattering (PVDIS) of electrons from protons and deuterons on the determination of the weak mixing angle, $sin^{2} θ_{W}$ , and parton distribution functions (PDFs) at large parton momentum fractions $x$ . Using the JAM global QCD analysis framework, we study the effect of incorporating pseudodata simulated for 11 GeV and 22 GeV Jefferson Lab kinematics, accounting for radiative corrections in a factorized QED+QCD approach and uncertainties from higher twist corrections in $γ Z$ exchange. We find that including future PVDIS pseudodata could yield important constraints on the value of $sin^{2} θ_{W}$ at low $Q^{2}$ and on the high- $x$ behavior of the strange quark and $d / u$ PDF ratio. The strong correlation between $sin^{2} θ_{W}$ and the $x$ dependence of the PDFs demonstrates the necessity for simultaneous analysis of QCD and electroweak quantities to ensure an unbiased determination of the weak mixing angle from PVDIS data.
hep-ph2 citations
27
Positron-Emitting and Electron-Capturing Double-Beta Processes in the Standard Model and Beyond
Lukáš Gráf🇨🇿 · Jenni Kotila🇫🇮 · Oliver Scholer🇩🇪
We study positron-emitting and electron-capturing double-beta-decay modes as probes complementary to the usual double beta decay. Motivated by the proposed NuDoubt++ experiment, we analyze the candidate isotopes $^{78}$ Kr, $^{106}$ Cd, and $^{124}$ Xe, providing nuclear matrix elements and phase-space factors for both neutrinoful and neutrinoless modes. For the Standard-Model channels, we find that $2 ν$ ECEC and $2 ν β^{+}$ EC are the most experimentally accessible, whereas $2 ν β^{+} β^{+}$ remains strongly phase-space suppressed. For the neutrinoless channel, we interpret a projected sensitivity of $T_{1/2}^{0 ν} = 1 0^{24}$ y in terms of dimension-seven SMEFT operators and find sensitivity to lepton-number-violating new-physics scales of order 1-100 TeV. We further show that measurements in multiple isotopes can help to resolve degeneracies in multi-operator scenarios, making positron-emitting double-beta searches a useful complement to conventional neutrinoless double beta decay experiments.
hep-phnucl-exnucl-th0 citations
28
Ab initio calculations of parity-violating electron scattering off $^{48}$ Ca and $^{208}$ Pb
Frederic Noël🇨🇭 · Matthias Heinz🇺🇸 · Martin Hoferichter🇨🇭 · Takayuki Miyagi🇯🇵 · Achim Schwenk🇩🇪
Parity-violating electron scattering off nuclei both serves as a low-energy precision probe to test electroweak interactions and allows one to access neutron distributions inside nuclei. It has implications for strong interactions in dense neutron-rich environments, also providing constraints for the properties of matter in neutron stars. Precision measurements are available for $^{48}$ Ca and $^{208}$ Pb by the CREX and PREX collaborations, respectively, and their interpretation requires advanced nuclear-structure calculations to draw firm conclusions. We perform the first ab initio calculations of the parity-violating asymmetry $A_{PV}$ based on nuclear forces from chiral effective field theory, fully including corrections due to Coulomb distortion effects. Based on these results, we critically reexamine correlation analyses employed to infer weak radii and quantify the resulting tensions between ab initio and experimental results. We find that ab initio calculations prefer values of $A_{PV}$ slightly smaller and larger than observed for $^{48}$ Ca and $^{208}$ Pb, respectively, with a global significance of $1.9 σ$ . Using theoretically consistent inputs for charge and weak densities, we infer from the experimental $A_{PV}$ a neutron skin of $^{208}$ Pb of $R_{n} - R_{p} = 0.187 (25) (18)$ fm, substantially smaller than that reported by PREX II.
↳ nucl-thastro-ph.HEhep-exhep-ph+12 citations
29
The swallowed spike: the formation of light primordial black hole structures around heavy seeds
Agnese Tolino🇪🇸 · Francesca Scarcella🇪🇸 · Bradley J. Kavanagh🇪🇸 · Valentina De Romeri🇪🇸 · Daniele Gaggero🇮🇹
Spikes are steep enhancements in the dark matter (DM) distribution around a heavy compact object. If the compact object is primordial, and the bulk of the DM is also composed of (lighter) primordial compact objects, for instance asteroid-mass primordial black holes (PBHs), the phenomenology of spike formation is highly non-trivial. In fact, lighter PBHs have negligible angular momentum at formation with respect to the massive central object and would therefore be captured unless enough torque is exerted from either small-scale or large-scale matter fluctuations. In this paper, we present the first comprehensive assessment of this scenario. We define the mechanisms and the initial conditions that allow light PBHs to avoid capture. We then quantify the different types of torque and follow the corresponding angular momentum evolution with a combination of analytical prescriptions and numerical simulations. We find that in the innermost region no mechanism studied here is capable of providing enough torque; the resulting inner core is expected to be significantly less dense than in particle scenarios, potentially leading to interesting phenomenology.
↳ astro-ph.COhep-ph0 citations
30
Symbiotic Magnetogenesis during Radiation Domination
Stephon Alexander🇺🇸 · Ariel Marxena Baksh🇺🇸 · Lawrence Edmond IV🇺🇸 · Wenrong Sun🇺🇸
We present a late-time magnetogenesis mechanism in which a coupled axion-dilaton system sources a dark $U (1)$ gauge field. The dilaton's exponential coupling drives tachyonic amplification by reshaping the instability band, while the axion controls the helicity structure of the field. Together, they amplify both gauge helicities and produce a moderately chiral dark magnetic field without fine-tuning in either scalar sector. The field is generated in the dark sector, thus the mechanism avoids plasma-conductivity suppression in the visible sector, while the model remains robust across a broad range of scalar-masses and couplings. Numerical evolution from $z = 1 0^{5}$ to matter-radiation equality, combined with a parameter search over the axion mass, dilaton initial conditions, and dilaton coupling, shows that astrophysically relevant amplification persists across fuzzy-dark-matter and ultralight-axion regimes. A benchmark case yields $B \approx 0.9 nG$ on $λ_{0} \sim 1 Mpc$ , with kinetic mixing transferring the field to the visible sector over a broad range of mixing parameters.
↳ astro-ph.HEhep-ph0 citations
31
Probing the Fundamental Nature of Particle Dark Matter
Marco Regis🇮🇹 · Aritra Basu🇩🇪 · Geoff Beck🇿🇦 · Gianni Bernardi🇮🇹 · Paolo Marchegiani🇮🇹 · Dominik J. Schwarz · Marco Taoso🇮🇹 · Elisa Todarello🇮🇹 · Emma Tolley · Cora Uhlemann
Understanding the fundamental nature of dark matter (DM) is one of the most significant scientific challenges of our time. A compelling hypothesis is that DM consists of a new, yet-to-be-discovered particle. Among the leading candidates are weakly interacting massive particles (WIMPs) and axion-like particles (ALPs), both of which can be investigated using observations with the SKA telescopes. In this chapter, we review the search for particle DM through radio observations, summarizing the current state-of-the-art and presenting forecasts for the SKA-Low and SKA-Mid telescopes in the AA4 baseline design. Radio searches for WIMPs focus on detecting synchrotron radiation originating from the products of DM annihilation using continuum observations. Competitive constraints on sub-TeV WIMPs have already been derived using SKA precursors looking at dwarf galaxies, galaxy clusters, and the Large Magellanic Cloud. We discuss how the superior continuum sensitivity of the SKA telescopes will allow us to progressively close in on the WIMP parameter space. The ALP signal arises from its decay or conversion into photon(s), which typically consists of a nearly monochromatic signature, and from rotation of polarization angles of photons interacting with ALPs. We demonstrate how the spectral resolution, line sensitivity, and polarimetry of the SKA AA4 telescopes can be leveraged to constrain the ALP-photon coupling.
↳ astro-ph.COhep-ph0 citations
32
Constraining supermassive primordial black hole clustering with the angular auto-correlation of $z ≃ 6$ quasars
Zhan-He Wang🇨🇳 · Hai-Long Huang🇨🇳 · Yun-Song Piao🇨🇳
High-redshift quasars provide a direct probe of the origin and environment of the earliest supermassive black holes. We use their angular auto-correlation function at $z ≃ 6$ to test scenarios in which supermassive primordial black holes (SMPBHs) are associated with the observed quasar population. The evolved PBH correlation functions, for both Poisson fluctuations and initial PBH clustering, are projected over the quasar redshift window and compared with the measured angular correlation function using Markov chain Monte Carlo inference. It is observed that for the Poisson model, the posterior favors a small abundance, $f_{PBH} \sim 1 0^{- 3}$ , and a supermassive effective mass scale, $m_{PBH} \sim 1 0^{12} M_{⊙}$ , interpreted here as a scale controlling quasar host-halo formation and clustering, and for the initially clustered model, the data prefer an effective clustering amplitude $ξ_{eff} ≃ 2.1$ and a top-hat boundary scale $r_{cl} ≃ 76 Mpc$ , corresponding to weak relative contraction of PBH pairs in comoving coordinates.
↳ astro-ph.COgr-qchep-ph0 citations
33
Parnassus: A GPU-enabled, Python-based Package for Fast Particle Detector Simulation and Reconstruction
Abdelrahman Elabd🇺🇸 · Eilam Gross🇮🇱 · Dmitrii Kobylianskii🇮🇱 · Benjamin Nachman🇺🇸
We present the public software release of Parnassus, a Python/PyTorch, GPU-compatible framework for fast detector simulation and reconstruction in particle and nuclear physics. Parnassus provides a user-friendly framework with interchangeable detector models: neural models can emulate computationally expensive Geant4-based detector simulation and reconstruction chains, while parametric models provide PyTorch implementations of selected Delphes-style detector responses. This initial release includes two models of the CMS detector: one based on a flow-matching neural network architecture and one based on a PyTorch implementation of the Delphes CMS card (parametric bias and smearing). PyTorch versions of the ATLAS and ALEPH Delphes cards are also available, together with a flow-matching neural model of the ALEPH detector that extends the framework to the e+e- LEP environment. All detector-specific backends share the same process-agnostic and detector-agnostic API: users select a detector card - analogous to choosing a detector card in Delphes - and the same tool can be applied to new physics processes without retraining the released detector model. There are native interfaces to the event generator Pythia and the event clustering package FastJet. Unlike previous C++/ROOT-based tools, Parnassus provides GPU-capable PyTorch detector-response backends and requires no ROOT installation. We describe the installation, command-line and Python API, configuration system, and demonstrate the framework on Standard Model and BSM processes.
↳ hep-exhep-ph1 citation

Affiliations

first authorsco-authorsvia INSPIRE