HEP Phenomenology·hep-ph

Thu·Jul 23, 2026Thursday·July 23, 2026

16 papers—6 primary·10 cross-listed

01
The Conformal Origin of the Lepton Flavor Mixing Matrix
Cora Aigle🇩🇪 · Alex Jourjine🇩🇪
Using the formalism of the flavor spin theory, we re-derive the TM1 lepton flavor mixing factor decomposition in a novel way, using a previously unreported near identity involving the elements of the first row of U_PMNS. The resulting mixing matrix is a direct consequence of the conformal symmetry of the massless SM before the EW phase transition. In addition to the previously reported results, we derive a relation between the CP violating phase and the three mixing angles. Application of the relation to the experimental data data suggests the TM1 decomposition should use (19/12)Pi as the value for the CP violating phase. With this assumption all four parameters of TM1 may be expressed in radicals, which might help in the separation of the classical values of the mixing parameters from their quantum corrections in the framework of the flavor spin theories. This in turn could help in clarification of the mass generation mechanism.
hep-phhep-th2 citations
02
Neutrino t-channels at Colliders: When Light Neutrinos Matter
Claudia Garcia-Garcia🇮🇹 · Manuel González-López🇪🇸 · Xabier Marcano🇮🇹 · Daniel Naredo-Tuero🇪🇸
Heavy Neutral Lepton (HNL)-mediated t-channel processes provide a unique opportunity to probe mass scales beyond the kinematic reach of direct production at high-energy colliders. We revisit these processes using the vector boson scattering channel $W W \to ℓℓ$ at the LHC as a case study, highlighting the essential role of the light neutrinos in restoring the proper high-energy unitary behavior of the scattering amplitude. Their inclusion, overlooked in some previous studies, leads to destructive interference that strongly suppresses lepton number violating signatures, demonstrating that a consistent treatment of the full seesaw spectrum qualitatively alters the phenomenology of t-channel HNL searches. This motivates the exploration of lepton number conserving but lepton flavor violating final states instead. We present a detailed analysis of the $pp \to e μ j j$ channel and show that it provides a promising probe of TeV-scale HNLs in low-scale seesaw scenarios with sizable active-sterile mixing, extending the LHC sensitivity beyond existing direct searches.
hep-phhep-ex0 citations
03
Higgs Couplings at a Future Wakefield Collider
Katherine Fraser🇺🇸 · Simon Knapen🇺🇸 · Kevin Langhoff🇺🇸 · Robert Szafron🇺🇸
We explore the potential of multiple possible future 10 TeV wakefield colliders to measure electroweak couplings of the Higgs boson. We find that the beam-beam interactions are not an impediment to high precision measurements of the Higgs couplings, provided that the luminosity spectra can be measured or calculated to high accuracy. In addition to $e^{+} e^{-}$ colliders, we also assess the effectiveness of alternatives such as $e^{-} e^{-}$ colliders or $γ γ$ colliders, which by-pass the positron acceleration challenge for wakefield colliders. We find that a 10 $ab^{- 1}$ dataset at a $γ γ$ collider yields qualitatively similar sensitivity to 10 $ab^{- 1}$ at a muon collider and 1 $ab^{- 1}$ at an $e^{+} e^{-}$ wakefield collider.
hep-ph2 citations
04
Can the universe be matter-dominated after a supercooled first-order phase transition?
Henda Mansour🇩🇪 · Yann Gouttenoire🇩🇪 · Felix Kahlhoefer🇩🇪
We show that the answer is generally no, at least not immediately. Bubble collisions leave behind a highly inhomogeneous scalar field with persistent relativistic gradients, producing an equation of state between matter and radiation. Using lattice simulations in one, two and three spatial dimensions, we find that the equation of state is controlled by the wall Lorentz factor at collision $γ_{⋆}$ : walls with larger $γ_{⋆}$ populate higher-momentum modes and drive the fluid closer to radiation. Matter domination begins only after these modes redshift, at $a / a_{⋆} ≃ γ_{⋆}$ , or after the field thermalises through self-scattering and number-changing processes. This delay has direct implications for gravitational waves, primordial black holes and dark matter production.
hep-phastro-ph.CO1 citation
05
Power of Axion Microwave Absorbed by Quantum Hall State in Haloscope
Aiichi Iwazaki🇯🇵
We propose a new method for detecting dark matter axions using haloscope coupled with a quantum Hall system. When a semiconductor sample exhibiting quantum Hall effect is placed inside the haloscope, two-dimensional ( 2D ) electrons absorb the axion induced radiation. We consider a GaAs sample with surface area $S = 10 cm^{2}$ and small thickness $≪ 1 mm$ . The power is $P_{s} ≃ 5.2 \times 1 0^{- 24} W (\frac{g _{γ}}{0.36})^{2} (\frac{B _{t}}{15 T})^{2} (\frac{V}{7.2 l}) (\frac{C}{0.6}) (\frac{ρ _{d}}{0.45 GeVc m ^{- 3}}),$ where $C$ denotes a form factor of the haloscope with volume $V = π R^{2} l ≃ π (\frac{2.4}{m _{a}})^{2} \times 1 0^{2} cm (\frac{l}{1 0 ^{2} cm}) ≃ 7.2 l$ ; $g_{γ} ≃ 0.36 (- 0.97)$ for DFSZ ( KSVZ ) axion model. We assume unloaded quality factor $Q_{0} = 1 0^{5}$ and quality factor of dark matter axion $Q_{a} = 1 0^{6}$ . The quality factor $Q_{s}$ of the sample is that $Q_{s} ≃ 1.1 \times 1 0^{6} (\frac{1 0 ^{- 5} eV}{m _{a}}) (\frac{10 cm ^{2}}{S}) (\frac{0.2 e ^{2} / h}{Re ( σ _{xx} )})$ , where we use measured longitudinal electrical conductivity $Re (σ_{xx}) ≃ \frac{0.2 e ^{2}}{h}$ ( Planck constant $h$ ) of quantum Hall state. When we put parallelly such $5$ thin samples with identical quantum Hall states, much larger power $P_{s} ≃ 1.5 \times 1 0^{- 23} W$ can be obtained. We have signal to noise ratio $≃ 2.3 (\frac{g _{γ}}{0.36})^{2} (\frac{B _{t}}{15 T})^{2} (\frac{100 mK}{T}) (\frac{1 0 ^{- 5} eV}{m _{a}})^{1/2} (\frac{V}{7.2 l}) (\frac{C}{0.6}) (\frac{ρ _{d}}{0.45 GeVc m ^{- 3}}) (\frac{δ t _{o b}}{100 s}) .$
hep-ph0 citations
06
Monopoles, Strings, Walls and Gravitational waves
Rinku Maji🇰🇷 · Qaisar Shafi🇺🇸
The gauge symmetry breaking $S U (2) \to U (1) \to Z_{2} \to 1$ successively produces monopoles, strings and domain walls bounded by strings (WBS), with the elementary monopole carrying a $U (1)$ magnetic flux twice as large as the elementary string. The elementary strings and subsequently WBS emit gravitational waves, and during their decay, the WBS yield a network of composite strings that carry the same $U (1)$ flux as the monopoles. Depending on the cosmological evolution, we provide the gravitational wave spectra generated by the elementary strings and WBS, in combination with the composite strings which are either effectively stable, quasistable, or metastable. These three scenarios are also realized in the symmetry breaking chain $S U (3) \to S O (3) \to Z_{2} \to 1$ . Both $S U (2)$ and $S U (3)$ have appeared in the literature as flavor gauge symmetries.
hep-phastro-ph.COhep-th0 citations
07
How many degrees of freedom describe a quantum N-particle state?
Matthew J. Lake🇷🇴 · Marek L. Miller🇩🇰
In Newtonian spacetime, the canonical description of a classical $N$ -particle system requires $3 N$ degrees of freedom. Not all of these are physical, however, since the conservation of the net momentum implies that only $3 (N - 1)$ accelerations are independent. Hence, three constraints can be used to eliminate the unphysical centre-of-mass variables, at the level of the Lagrangian, leaving only the subset of observable displacements and momenta, which are relational. Imposing the constraints does not change the dynamics of these variables, at the classical level, and is analogous to a gauge-fixing procedure, which removes redundancy in the description of the system. In classical physics, therefore, the number of physical degrees of freedom equals the number of independent relational degrees of freedom. Here, we show that this is not the case in quantum mechanics. While an operator-analogue of the classical net momentum exists, it cannot be used to impose constraints that restrict the degrees of freedom in the theory, without a loss of physical information. This means that all $3 N$ canonical degrees of freedom are physical, even though only $3 (N - 1)$ of them are relational. We explore the physical consequences of the non-relational variables and show that they give rise to generalised uncertainty relations (GURs), for the relational quantities that define the quantum reference frame (QRF). Hence, it is shown that the non-relational degrees of freedom refer to the frame itself and that the non-Heisenberg terms in the GURs define its Galilean-invariant spreads, in both real space and momentum space. The implications of this result for recent work on relational models, including the ``perspective neutral'' framework for QRFs, are discussed. Its implications for the wider relational program, and, in particular, the relevance of the latter to quantum gravity research, are also critically assessed
↳ quant-phgr-qchep-ph0 citations
08
Confinement Versus Screening in the Schwinger Model on AdS $_{2}$ from Bosonization and Tensor Networks
Sriram Bharadwaj🇺🇸 · Jack Isen🇺🇸 · Zhong-Bo Kang🇺🇸
We analyze confinement and screening in single-flavor quantum electrodynamics (QED $_{2}$ ) on two-dimensional anti-de Sitter space (AdS $_{2}$ ), with and without a Schwarzschild black hole, both in the continuum and on the lattice. The theory is formulated in two frames adapted to distinct choices of a preferred time coordinate: the Schwarzschild frame, associated with the Boulware vacuum, and the global AdS $_{2}$ frame, associated with the $SL (2, R)$ -invariant vacuum. In the massless limit, the static potential between an external charge-anticharge pair is obtained in closed form by bosonization, at both zero and finite temperature. After subtraction of the position-dependent probe self-energies, which, unlike in flat space, are not constant, the potential remains finite as the geodesic separation is taken to infinity, establishing that the theory is screened. This is consistent with the explicit breaking of the $U (1)$ electric one-form symmetry by the dynamical fermions, and resolves a confining/screening ambiguity in earlier treatments that identify the static potential with the unsubtracted ground-state energy. To validate the continuum analysis, we propose a covariant discretization scheme for placing fermions in curved spacetime on the lattice while ensuring that the continuum properties of the spin and gauge connections are restored in the continuum limit. This construction resolves ambiguities in the existing literature on lattice fermions in curved backgrounds and provides the foundation for our tensor-network simulations. Using a matrix product state ansatz, we confirm our analytical predictions for the phase diagram in AdS $_{2}$ . We perform extensive numerical simulations of the static potential and the electric flux-tube profile for varying fermion masses, which we match to the continuum prediction.
↳ hep-thhep-lathep-phquant-ph1 citation
09
Four, One, and None: Quantifying the Ultra-High-Energy Neutrino Anomaly Across ANITA-IV, KM3NeT, and IceCube
Dibya S. Chattopadhyay🇺🇸 · Carlos A. Argüelles🇺🇸 · Vedran Brdar🇺🇸
The four near-horizon neutrino-like events reported by ANITA-IV and the ultra-high-energy track-like event KM3-230213A observed by KM3NeT imply neutrino event rates that are in tension with the absence of corresponding events at IceCube. In this work, we perform a joint analysis of these events, taking into account the absence of any corresponding ones at IceCube. We construct semi-analytic, energy- and direction-dependent effective areas for the three detectors and account for the time-dependent ANITA-IV and KM3NeT exposures. For a diffuse all-sky power-law flux varying both the normalization and the spectral index, the measured event rates across the three detectors are not reproduced. The best-fit configuration, corresponding to a tension of $\sim 7.5 σ$ , predicts approximately five IceCube events while strongly underpredicting the ANITA-IV and KM3NeT counts. In contrast to the diffuse scenario, the tension can be substantially alleviated if the events arise from short-duration transients that occur exactly along the observed directions during the ANITA-IV and KM3NeT detection windows. Such a realization, however, is highly fine-tuned. If rare transients are instead distributed randomly across the full sky over the $\sim 15$ -year IceCube observation period, additional sources inevitably contribute to the IceCube exposure. For benchmark populations with a probability of approximately $1 0^{- 4}$ to produce four favorable transients at ANITA-IV, the best-fit configuration of sources, out of $1 0^{5}$ Monte Carlo realizations, remains in $5.9 σ$ tension. We conclude that, within the Standard Model, directional and temporal variations alone can not reconcile the ANITA-IV and KM3NeT observations with the IceCube null result, under both a diffuse all-sky flux and a rare-transient source hypothesis.
↳ astro-ph.HEhep-exhep-ph1 citation
10
Chiral Magnetic Conductivity in the Tight-Binding Model of Dirac Semimetals
Mustafa Bohra · Yuexiang Zhang · M.A. Zubkov🇮🇱
We consider the typical tight - binding model of Dirac semimetal in the presence of both magnetic and electric fields. The electric conductivity reveals dependence on magnetic field. We calculate this dependence in the limit of strong magnetic field, when the given model is described effectively by the one - dimensional SSH model because the dynamics in the plane orthogonal to magnetic field is reduced to that of the lowest Landau level (LLL). Considering the small temperature limit we take into account dissipation due to scattering on impurities. The corresponding dissipation rate is calculated explicitly. The obtained results confirm that the source of the magnetoconductivity in this system is chiral magnetic effect.
↳ cond-mat.mes-hallhep-ph0 citations
11
Intermittency in Quantum Graviton-Phonon Conversion
Yuna Gouin🇫🇷 · Sugumi Kanno🇯🇵 · Jiro Soda🇯🇵
A graviton can be converted into a phonon in a resonant bar detector. First-order perturbation theory predicts a strong enhancement of this conversion for coherent and squeezed graviton states, but the probability can exceed unity when the coherent or squeezing parameter is large. Since a conversion probability must satisfy the unitarity bound, we solve the graviton-phonon quantum dynamics exactly within the rotating-wave approximation. For an initial coherent state, we find that the conversion occurs intermittently through narrow bursts separated by intervals of strong suppression. For an initial squeezed state, the departure from perturbative behavior occurs earlier, and the conversion is strongly suppressed after its initial growth. These effects may provide signatures of quantum graviton-phonon dynamics relevant to single-graviton detection.
↳ gr-qchep-phquant-ph1 citation
12
Diffractive Two-Photon Exchange and Beam Normal-Spin Asymmetries for Elastic Electron Scattering on Nuclei
Volodymyr Tereshchuk🇺🇸 · Andrei Afanasev🇺🇸
We developed a theoretical approach to elastic electron scattering on nuclei that includes a two-photon-exchange mechanism responsible for parity-conserving single-spin beam asymmetries. The two-photon-exchange amplitude at small scattering angles is treated in a diffractive framework similar to that of pion-nucleus elastic scattering applied to the nuclei $_{6}^{12}$ C, $_{20}^{40}$ Ca and $_{82}^{208}$ Pb. The predicted kinematic features of the beam polarization asymmetries for different nuclei may reconcile Jefferson Lab's experimental results at finite scattering angles with a forward limit given by an optical theorem, potentially resolving the so-called ``PREX Puzzle" for $_{82}^{208}$ Pb.
↳ nucl-thhep-ph0 citations
13
Fabrication status and expected performance of the inner-core X-ray optic for BabyIAXO
Jooyun Woo🇺🇸 · Yue Yu🇨🇦 · Ipek Altunyurt · Todd Decker · Desiree Della Monica Ferreira · Peter Lindquist Henriksen · Eftychia Kotsiou · Sonny Massahi · Kerstin Perez🇺🇸 · Anacorina Romero🇺🇸 · Jaime Ruz🇩🇪 · Vyshnavi Sabbi · Marcela Stern🇺🇸 · Julia Katharina Vogel🇩🇪
BabyIAXO, a pathfinder for the International Axion Observatory (IAXO), is designed to demonstrate all key technologies at scale while achieving an improvement in sensitivity over the recent CERN Axion Solar Telescope (CAST) experiment by approximately a factor of five. Such improvement is enabled by the X-ray optics, which allow for maintaining a high signal-to-noise ratio at the detector despite a cross-sectional area of the magnetic bore being over 250 times larger than that of CAST. The optic employs a hybrid design consisting of co-aligned inner core and outer corona optics that share a common optical axis and vacuum vessel but differ in focal length and manufacturing approach. Both are segmented glass optics, with the inner core fabricated from thermally slumped borosilicate glass and the outer corona from cold-slumped Corning Willow glass. To fabricate the inner-core optic, leveraging techniques developed for NuSTAR and HEFT optics, we reoptimized and streamlined the thermal-forming procedure. The quality of free-standing glass substrates was characterized by laser metrology, X-ray reflectometry, and atomic force microscopy. We developed a cutting technique that produces smooth edges at the micron scale. We used flat stacks of glass-epoxy-graphite layers to evaluate the performance of the epoxy bondline. The optic is expected to achieve an on-axis point spread function (PSF) with a half-power diameter (HPD) of < 90", enhancing the signal-to-noise ratio by more than 55 times.
↳ physics.ins-detastro-ph.HEastro-ph.IMhep-ex+10 citations
14
Classical Hardware Acceleration of Quantum Autoencoders for Real-Time Anomaly Detection in Collider Experiments
Ivan Ge🇺🇸 · Sagar Addepalli🇺🇸 · Abhilasha Dave🇺🇸 · Julia Gonski🇺🇸
Quantum machine learning (QML) algorithms in high energy physics (HEP) can efficiently represent and leverage long-range, high-order correlations in high-dimensional collider data, potentially with fewer parameters and favorable scaling relative to classical models. Deployment of QML in real-time collider applications such as trigger systems requires the ability to emulate and compile quantum circuits classically, then synthesize the resulting quantum gates onto low-latency hardware accelerators, namely field-programmable gate arrays (FPGAs). We present a study of variational quantum autoencoder models for real-time anomaly detection triggers in modern collider experiments. The models achieve performance comparable to state-of-the-art classical approaches and, after FPGA synthesis, satisfy resource usage and timing constraints consistent with trigger applications in future colliders. This work provides one of the first FPGA implementations of QML models for HEP triggers, enabling higher-capability models in today's classical data acquisition pipelines while advancing quantum readiness of collider experiment infrastructure.
↳ cs.LGhep-phphysics.ins-det1 citation
15
Interacting Dark Energy and Dark Matter in O(3) No-Scale Gravity
Lincoln da S. Pereira🇧🇷 · Muzi Hong🇯🇵 · Elisa G. M. Ferreira🇯🇵 · Tsutomu T. Yanagida🇯🇵
Dark Energy (DE) and Dark Matter (DM) are among the greatest mysteries in particle physics and cosmology, since their origins remain unclear. It is intriguing to consider whether both may originate from a purely gravitational sector. We propose that they arise from degrees of freedom associated with the partners of the Brans-Dicke boson in No-Scale Gravity, a fundamental scale-invariant gravitational theory in which the Planck scale is illusional. We consider the Brans-Dicke boson, together with two scalar fields, to form a vector multiplet under an $O (3)$ symmetry, whose angular directions in the Einstein frame are identified with DM and DE. Small explicit breaking of $O (3)$ generates their masses and interaction, and we show that the resulting model reproduces the required background cosmological evolution and present-day abundances, with the lighter field providing a dynamical DE component at late times. Although the DE field remains canonical, the interacting cosmology exhibits an effective phantom-like evolution at late times, of the type suggested by DESI in combination with other cosmological probes, without introducing a fundamental phantom degree of freedom. The model provides a first-principles realization of interacting DE, in which DM, DE, and their coupling emerge from the symmetry structure of the underlying gravitational theory.
↳ astro-ph.COgr-qchep-phhep-th2 citations
16
Nucleon unpolarized second Mellin moments using lattice QCD ensembles with physical quark masses and in the continuum limit
Constantia Alexandrou🇨🇾 · Simone Bacchio🇨🇾 · Jacob Finkenrath🇩🇪 · Christos Iona🇨🇾 · Giannis Koutsou🇨🇾 · Christian Kummer🇨🇾 · Yan Li🇨🇾 · Bhavna Prasad🇨🇾 · Gregoris Spanoudes🇨🇾
We compute the matrix elements of the energy-momentum tensor of the nucleon using four ensembles of twisted mass clover-improved fermions with the up, down, strange and charm quark masses tuned to approximately their physical values. The four ensembles have similar physical volume and lattice spacings $a = 0.080$ ~fm, $0.068$ ~fm, $0.057$ ~fm, and $0.049$ fm, allowing us to take the continuum limit directly at the physical pion mass point. We compute both connected and disconnected quark contributions as well as gluon contributions. All renormalization functions, including the mixing of the quark singlet with the gluon, are determined non-perturbatively. We extract the gravitational form factors in the continuum limit at $Q^{2} = 0$ and evaluate the contribution of quarks and gluons to the momentum and angular momentum of the proton. Using the values of the intrinsic quark spin computed using the same gauge ensembles we also determine the orbital angular momentum for each quark flavor.
↳ hep-lathep-exhep-phnucl-ex+11 citation

Affiliations

first authorsco-authorsvia INSPIRE