HEP Phenomenology·hep-ph

Tue·Oct 6, 2026Tuesday·October 6, 2026

21 papers—16 primary·5 cross-listed

01
An optimal observable for polarization measurements
Erik Bachmann · Mareen Hoppe
Vector-boson polarization provides a sensitive probe of new physics in the electroweak sector. Rare processes and suppressed longitudinal contributions make optimal polarization separation essential to exploit the available data. We show that parton-level differential polarization fractions define optimal observables and a fundamental sensitivity limit for polarized cross-section measurements. Their conditional expectations retain all experimentally accessible polarization information, yielding the best achievable sensitivity within the assumed model, and can be learned by neural networks for unbinned or binned inference. Measuring their distributions combines polarization sensitivity with the model independence of fiducial cross sections, probing deviations beyond constant rescalings of polarized contributions. We demonstrate the approach in inclusive ZZ production.
hep-phhep-ex
02
No Einstein Relation, No Problem: How Relativistic Weakly Coupled Heavy Quarks Equilibrate Beyond Leading Logarithm Anyway
Jean F. Du Plessis · Bruno Scheihing-Hitschfeld
Relativistic heavy quarks equilibrate even when their microscopic drag and momentum diffusion violate the Einstein relation. We investigate how equilibration proceeds as a function of the coupling and compared to simplified Fokker-Planck models. To do this, we present a detailed calculation of the momentum-transfer kernel in weakly coupled non-Abelian plasmas through strict $O (g^{4})$ , and study the resulting dynamics at leading order in the inverse heavy-quark mass. Beyond leading logarithm, its non-Gaussian structure plays a crucial role in equilibration. We examine closely the analytic structure of the evolution kernel, determine the large-order asymptotics of the momentum-transfer cumulants, and show how the kernel's bounded analytic domain fixes asymmetric exponential tails at the level of the momentum transfer probability. Strongly coupled $N = 4$ SYM also features an approximately Gaussian core and exponential tails, but differs in the nature of the kernel's singularities and the velocity dependence of the transport coefficients and tail exponents. These differences have distinct dynamical consequences: for the parameters studied, the persistence of the relativistic population in steeply falling spectra is largely explained by drag alone at very weak coupling, whereas fluctuation-induced survivor bias produces a large relative enhancement at strong coupling. Nevertheless, the shared qualitative structure between weak and strong coupling points the way towards a practical phenomenological description of heavy quarks anchored in first-principles field theory.
hep-phhep-thnucl-th
03
A Powheg generator for $t$ - and $s$ -channel single-top production and decay including non-resonant effects
Melissa van Beekveld · Robin van Bijleveld · Silvia Ferrario Ravasio · Tomas Jezo · Tommaso Saracco
We present a next-to-leading order + parton shower generator for $t$ - and $s$ -channel single-top production in hadron colliders, for a leptonically-decaying top, including off-shell and non-resonant effects. The generator, publicly available in the POWHEG BOX RES framework, describes the hadro-production of a $b$ -jet and a leptonically decaying $W$ -boson, accompanied by an additional jet, i.e. $pp \to ℓ^{+} ν_{ℓ} j_{b} j$ and $pp \to ℓ^{-} ν ˉ_{ℓ} j_{b ˉ} j$ , where $j_{b}$ ( $j_{b ˉ}$ ) is a jet containing a bottom (anti)quark, and $j$ is a generic jet. We also provide an interface to the Pythia parton shower, suited to matching in the presence of decaying resonances such as the top quark. Our matching is designed to combine the advantages of a five-flavour calculation with the description of bottom quark mass effects in final-state jets. We perform a phenomenological study using fiducial cuts and discuss shower effects.
hep-phhep-ex
04
Reinterpreting ATLAS Dijet and Supersymmetry Searches in A Baryon-Number-Violating Heavy Scalar Framework
Tianyi Yang · Denis Rathjens · Alfredo Gurrola · Francesco Romeo
A reinterpretation of ATLAS searches targeting $b$ -tagged dijet resonances and monotop-alike signatures at a center-of-mass energy of 13 TeV is presented using $pp$ collision data corresponding to integrated luminosities of 139 $fb^{- 1}$ . These searches are used to constrain a baryon-number-violating new physics model that introduces two scalar mediators $X_{1}$ and $X_{2}$ to simultaneously address the baryon asymmetry of the universe and the dark matter relic abundance. By exploiting heavy-flavor signatures and allowing for jet-rich final states, this reinterpretation provides complementary sensitivity to the model relative to non-flavor-tagged inclusive dijet searches and conventional monotop reinterpretations. Assuming the mediators decay either into a pair of down-type quarks or into a top quark and a dark matter candidate, we translate the experimental upper limits into the model's parameter space. 95% confidence level exclusion limits are derived in the $λ_{1}$ - $λ_{2}$ coupling plane for benchmark mediator masses of 1.5, 1.75, and 2.0 TeV. For all three benchmark masses, the $b$ -tagged dijet reinterpretation excludes $λ_{1} > 0.45$ , while the bottom-squark reinterpretation excludes the region with $λ_{1} > 0.3$ and $λ_{2} > 0.6$ , within the respective validated parameter domains.
hep-phhep-ex
05
Dijet acoplanarity as a function of flattenicity in proton-proton collisions at $s = 13$ TeV
Jesus Eduardo Muñoz Mendez · Antonio Ortiz
One of the most important discoveries at the LHC is the presence of effects associated with quark-gluon plasma (QGP) formation in proton-proton (pp) collisions. The origin of these observations remains unknown. Since event selection in many studies relies on multiplicity-based estimators known to introduce selection biases, alternative approaches must be explored to elucidate the origin of these phenomena. This contribution presents a comparison of different event classifiers used in LHC experiments, aiming to assess their mutual compatibility. Results for pp collisions at $s = 13$ TeV simulated with PYTHIA 8 indicate that the different classifiers introduce biases that can obscure any evidence of QGP formation in small systems. However, these biases are significantly reduced or absent in events triggered with flattenicity. This finding motivates the application of flattenicity in dijet acoplanarity studies used to search for jet quenching effects. While multiplicity-based estimators produce an azimuthal broadening in high-multiplicity compared with minimum-bias pp collisions, even in PYTHIA 8 that does not incorporate jet quenching, events triggered with flattenicity show no such broadening. This suggests that this novel tool could be exploited by LHC experiments to refine jet-quenching searches in small systems.
hep-ph
06
Energy shift and decay width of kaonium from coupled-channel one-loop chiral amplitudes
Alireza Beygi
Using two fitted coupled-channel one-loop chiral amplitudes, we investigate the strong-interaction energy shift and decay width of the hypothetical Coulomb-bound $K^{+} K^{-}$ hadronic atom, kaonium. We obtain ground-state widths of 1.67 and 0.92 keV, which are both larger than previous kaonium predictions, including the 0.30 keV result obtained from a non-perturbative treatment based on leading-order chiral perturbation theory. Although the $K^{+} K^{-}$ scattering lengths obtained from the two one-loop amplitudes have nearly equal imaginary parts, their real parts have opposite signs; thus, the leading absorptive contributions to the widths are similar, while the Coulomb corrections act in opposite directions. The kaonium width therefore depends on both the real and imaginary parts of the near-threshold strong amplitude. Despite the increased ground-state width, the first three $s$ -wave levels remain separated. In photon fusion, at fixed pole area and resonance position, the increase in the intrinsic width has a negligible effect on the line shape after including Belle's experimental resolution.
hep-ph
07
Spontaneous Spin Polarization in Dense Quark Matter Reexamined
Carlisson Miller · Rodolfo Casana · Manoel M. Ferreira · Gastão Krein
The phase structure of strongly interacting matter at high baryon density remains an open problem in QCD, with important implications for the internal structure and magnetic properties of neutron stars. We reexamine the emergence of a quark spin-polarized (QSP) phase in cold, dense quark matter within the two-flavor Nambu-Jona-Lasinio model with tensor interactions, focusing on its dependence on regularization. We compare the traditional regularization scheme (TRS), where a sharp momentum cutoff is applied to both vacuum and medium contributions, with the medium separation scheme (MSS), where ultraviolet-divergent vacuum terms are isolated while finite medium-dependent phase-space contributions remain cutoff free. The two prescriptions lead to qualitatively different results. In TRS, the QSP condensate eventually collapses at high chemical potential, leading to nonmonotonic thermodynamic behavior and, for some couplings, violations of causality. In MSS, the QSP condensate instead increases monotonically with density, the equation of state remains causal, and the associated spontaneous magnetization grows toward high density. The persistence of spin polarization at high density may provide a microscopic contribution to the strong magnetic fields of compact stars, including magnetars. An exploratory hybrid-star construction further shows that the QSP phase can significantly modify the equation of state, stability trends, and mass-radius relations. These results highlight the importance of a consistent treatment of medium phase space and demonstrate the potential impact of a persistent spin-polarized quark phase on neutron-star physics.
hep-ph
08
A Composite Three-Body-Holonomy Toy Framework for Dynamical Electroweak-Scale Selection
Tadashi Yoshikawa
We propose a phenomenological toy framework promoted to a minimal three-state internal sector in $(3 + 1)$ dimensions and realized by composite strong dynamics. It is in a genuine three-body holonomy which originates in a relativistic $(1 + 1)$ -dimensional Dirac system. The hypothesis is that the number three is not imposed first as a gauge symmetry, but is inherited from the primitive closed cyclic structure of the three-body holonomy. This threefold structure subsequently reappears as a three-state internal space, the three-site loop, a three-flavor hidden sector, and a cubic determinant interaction. We introduce an asymptotically free hidden $S U (3)_{H}$ gauge theory with three Standard-Model-singlet Dirac flavors. Strong hidden dynamics generates a composite condensate, while the inherited holonomy selects its cyclic internal orientation. The anomalous cubic determinant interaction produces a holonomy-dependent potential, and dimensional transmutation generates the characteristic composite scale. The radial composite excitation along the cyclic direction, denoted by $S_{3}$ , couples to the Standard-Model Higgs doublet through a holonomy-dependent CP-even portal. The resulting condensate shifts the Higgs quadratic term and can trigger electroweak symmetry breaking. In the classically scale-invariant reference limit, the electroweak scale is induced from the dynamically generated hidden-sector scale through dimensionless portal couplings.
hep-ph
09
Pseudo-Nambu-Goldstone Boson Motion from Thermal Thresholds
Mussawir Khan · Ali Muhammad · Tianjun Li
Coherent motion of light scalar fields in the early Universe is typically attributed to an initial displacement, a primordial velocity, or a prescribed temperature-dependent potential. We identify a distinct microscopic mechanism in which differential thermal evolution of multiple non-aligned symmetry-breaking sources rotates the effective vacuum direction of a pseudo-Nambu--Goldstone boson (pNGB), driving motion from an initially stationary minimum. The mechanism is realized in the Majoron sector of a Type-I seesaw mechanism, where heavy neutrinos with separated thermal thresholds supply the required differential thermal evolution. For a representative benchmark, the thermal source direction rotates by $∣Δ θ_{T} ∣ ≃ 0.76$ ~rad and drives the Majoron to a peak velocity $∣ θ ˙ ∣/ H ≃ 0.62$ , while the field tracks the moving minimum to sub-milliradian accuracy. This establishes a microscopic finite-temperature origin for pNGB motion, with implications for spontaneous leptogenesis and, more generally, for any system with multiple non-aligned symmetry-breaking sources that evolve differently with temperature.
hep-ph
10
Amplitude-level NLO predictions for exclusive $J / ψ + γ$ production in ultraperipheral collisions
Xi-Jie Zhan · Tai-Fu Feng · Xing-Gang Wu
Exclusive $γ γ \to J / ψ + γ$ production is studied in the color-singlet channel at leading order in the heavy-quark velocity. The conventional next-to-leading-order (NLO) result $B + V$ , comprising Born production and its interference with the renormalized one-loop amplitude, is compared with $B + V + Q$ , where $Q$ retains the complete one-loop square. At photon-photon energies $W = 80 GeV$ and $160 GeV$ , the conventional spectrum becomes negative over finite high- $p_{T}$ intervals already at renormalization scale $μ_{R} = W$ , whereas the complete square remains non-negative. In contrast, the total partonic cross section exceeds Born at the larger energies in the energy scan, owing to positive virtual contributions from other scattering directions. For $p$ - $p$ collisions at $14 TeV$ and $P b$ - $P b$ collisions at $s_{N N} = 5.52 TeV$ , $Q$ raises the central integrated ultraperipheral rates by $11.6%$ -- $18.4%$ . Their absolute scale widths over $μ_{R} = {W /2, W, 2 W}$ decrease by $36%$ -- $67%$ . Retaining the complete one-loop square changes both the predicted integrated rates and the shapes of the differential distributions.
hep-ph
11
Angular Observables in the $Λ_{b} \to Λ ν ν ˉ$ Decay
Wolfgang Altmannshofer · Shibasis Roy
We study the rare decay $Λ_{b} \to Λ (\to p π^{-}) ν ν ˉ$ of polarized $Λ_{b}$ baryons produced at the $Z$ pole. We find that the differential decay distribution is characterized by five independent angular observables, four of which require initial $Λ_{b}$ polarization. While standard observables in mesonic $b \to s ν ν ˉ$ decays ( $B \to K^{(*)} ν ν ˉ$ , $B_{s} \to ϕ ν ν ˉ$ ) probe only two combinations of short-distance Wilson coefficients, $∣ C_{L} + C_{R} ∣$ and $∣ C_{L} - C_{R} ∣$ , the angular observables in $Λ_{b} \to Λ (\to p π^{-}) ν ν ˉ$ provide access to the orthogonal combinations $∣ C_{R} ∣^{2} - ∣ C_{L} ∣^{2}$ and $Im (C_{L} C_{R}^{*})$ . In particular, we identify a $T$ -odd CP asymmetry, $A_{5}$ , that directly probes CP-violating phases in the short-distance effective Hamiltonian. We present Standard Model predictions for the branching ratio and all angular observables using lattice QCD form factors, and evaluate the projected new physics sensitivity at the FCC-ee. Our results demonstrate that baryonic angular observables are essential for resolving parameter degeneracies and for completely characterizing the chiral and CP structure of possible new physics in $b \to s ν ν ˉ$ transitions.
hep-phhep-ex
12
Chiral Vortical Transport under Minimal-Length Deformations in Rotating Relativistic Matter
Sameer Ahmad Mir · Behnam Pourhassan · Nawal H.Siddig · Euaggelos E. Zotos · Laila Abdulaziz Al-Essa
We study how a minimal length can affect the chiral vortical effect, in which rotation produces a current in matter made of chiral fermions. We focus on an isotropic modification of the momentum-space density-of-state (DoS) and determine the vortical conductivity from the static, long-wavelength correlation between the current and momentum density. The analysis is carried out first for a single right-handed Weyl fermion and is then extended to general massless chiral fermion systems with mutually commuting conserved charges. We find that, for a broad class of analytic isotropic DoS modifications, the familiar leading contributions from chemical potential and temperature remain unchanged at first order within the DoS sector. Minimal-length effects instead appear through higher-order thermal and chemical-potential contributions. Some of these corrections contain the same chiral charge combinations that appear in gauge and mixed gauge-gravitational anomalies, while another contains an independent higher-order charge combination. Their coefficients depend on the form of the DoS modification and are therefore not fixed by the usual four-dimensional anomaly structure. For the Kempf-Mangano-Mann deformation, the exact result shows that a positive minimal-length parameter always reduces the DoS contribution to the vortical conductivity. We also find that a Planck-suppressed correction is extremely small under standard heavy-ion chemical freeze-out conditions. These results show that isotropic minimal-length modifications can change higher-order contributions to chiral vortical transport while leaving the familiar leading anomaly-related response unchanged within the DoS sector considered here.
hep-phEur.Phys.J.Plus 141 (2026) 9, 1104
13
Freeze-in Asymmetric Dark Matter with a Dual-Role Scalar: CP Violation and Symmetric-Component Depletion
S. Peyman Zakeri
We present a minimal, predictive scenario for asymmetric fermionic dark matter (DM) generated through freeze-in. The standard model (SM) is extended by a Dirac fermion $ψ$ that serves as the DM candidate, an auxiliary Dirac fermion $χ$ , a real scalar mediator $ϕ$ , and a heavier real scalar $S$ , all stabilized by a $Z_{2} \times Z_{2}^{'}$ discrete symmetry. The DM asymmetry is generated through the CP-violating out-of-equilibrium decays of the mediator $ϕ$ , while the heavier scalar $S$ plays a dual role: it generates the physical CP-violating phase required for the asymmetry through its interference with $ϕ$ , and it mediates the annihilation of the symmetric component of the DM population. We solve the coupled Boltzmann equations for the asymmetric yield $Y_{-}$ and the total yield $Y_{Σ}$ , and identify the scaling relations $Y_{-}^{\infty} \propto μ^{2} ε / m_{ϕ}$ and $Ω_{DM} h^{2} \propto m_{ψ} μ^{2} ε / m_{ϕ}$ , which we verify numerically. The observed relic abundance $Ω_{DM} h^{2} ≃ 0.12$ is naturally reproduced for a wide range of parameters; in particular, for $ε = 1 0^{- 6}$ and $m_{ϕ} = 200$ ~GeV, the correct relic density is obtained for $μ \approx 2.7 \times 1 0^{- 9}$ ~GeV and $m_{ψ} \approx 40$ ~GeV. We further confront the model with current experimental constraints, including direct detection, indirect detection, collider searches, and DM self-interactions, and show that the predicted signals lie far below the sensitivity of current experiments. This scenario provides a self-consistent and testable realization of asymmetric fermionic DM within the freeze-in framework.
hep-ph
14
Pion gravitational form factors in an algebraic rainbow-ladder model
Jiayin Kang · Lei Chang
Within rainbow-ladder truncation, we identify three contributions to the pion's gravitational form factors---graviton coupling to the quark, to the gluon dressing the quark, and to the gluon binding the pion---and separate them into quark and gluon parts. Using an algebraic quark model with a dynamical basis, we obtain $A (0) = 1$ , $D (0) = - 1$ in the chiral limit, and momentum fractions $⟨ x ⟩_{q} = 0.896$ , $⟨ x ⟩_{g} = 0.104$ . The D-term obeys the same partition at the model scale.
hep-ph
15
Precision Electroweak Physics of Neutral Currents Below the Z-pole
Jens Erler · Krishna S. Kumar
We report on the status and prospects of precision weak neutral current interaction measurements in fixed target scattering, atomic parity violation, as well as future collider measurements at momentum transfer $Q^{2} ≪ M_{Z}$ , including the experiments in parity-violating electron scattering under construction at Jefferson Laboratory and at Mainz that are expected to commence data collection in the very near future.
hep-phnucl-ex
16
Violation and Restoration of Probability Positivity in Perturbative Quantum Field Theory: From Quantum Mechanics to Quantum Chromodynamics
Bin Gong · Xu-Dong Huang · Jian-Xiong Wang · Chao Zeng
In quantum mechanics the modulus square of the wave function is the probability of an event --- positivity is self-evident. Quantum field theory corresponds to quantum mechanics one-to-one: the wave function corresponds to the matrix element, so the probability of a process should be the modulus square of the matrix element, positive by construction. In the founding era of perturbative quantum field theory, however, Feynman, Schwinger and Tomonaga treated inclusive processes in quantum electrodynamics, where the truncation of the squared amplitude was forced by infrared cancellations and rendered harmless by the small coupling $α ≃ 1/137$ . Carried over to exclusive processes in quantum chromodynamics, where the coupling is large, this practice produced negative decay and production rates already at NLO, persisting at NNLO. We point out that for exclusive processes, whose initial and final states are colorless for QCD and electrically neutral for QED, the infrared divergences cancel amplitude by amplitude and the KLN constraint is absent, so the complete modulus square of the truncated amplitude is the proper, manifestly positive definition of the probability. We formulate amplitude-level NRQCD factorization as the systematic prescription that restores positivity, show that every amplitude-level truncated observable admits the effective representation $Γ^{amp} = Γ_{LO} 1 + \frac{α _{s}}{π} (c_{1} + i c_{2}) + \frac{α _{s}^{2}}{π ^{2}} (c_{3} + i c_{4})^{2}$ , and demonstrate, with the complete NNLO QCD corrections to $J / ψ \to 3 γ$ , $Υ \to 3 γ$ , $e^{+} e^{-} \to J / ψ + J / ψ$ and the eight exclusive charmonium production channels at $B$ factories, that the prescription yields positive and better-converging predictions.
hep-ph
17
Nonlinear completions of the Ricci coupling in black-hole scalarization
Subrat Parida
We study spontaneous scalarization of static, spherically symmetric black holes in scalar--Gauss--Bonnet gravity with a Ricci coupling $F = 1 β ϕ^{2} /4 + γ β^{2} ϕ^{4} + O (ϕ^{6})$ that nonlinearly completes the quadratic one. For arbitrary couplings and potential, we derive the near-horizon regularity condition and horizon curvature invariants in closed form; scalarized branches terminate where this condition degenerates, at finite horizon curvature. A weakly nonlinear expansion fixes the bifurcation direction exactly: for a massless scalar, its governing coefficient is quadratic in $β$ , changes sign at $β = 1.1156$ , and depends linearly on a quartic self-interaction. At equal horizon values of the scalar, completions differ in mass, to leading order, in proportion to $γ$ . A radial-perturbation master equation for arbitrary couplings confirms the exchange of stability at the bifurcation and turning points. Consequently, the domain of radially stable black holes shrinks as $γ$ increases over the range studied; it is smaller for the exponential completion than for the quadratic truncation.
↳ gr-qchep-phhep-thmath-ph+1
18
Comment on ''Chiral electromagnetic surface waves on Chern-Simons interfaces'' Phys.Rev.D114(2026)L051903 and on arXiv:2606.12513 by N. Kaloper
Igor Bandos · Bohdan Zvorskyi
We demonstrate that Maxwell electrodynamics interacting with a planar Chern-Simons interface does not have plane wave solutions localized on the interface. We re-examine the derivation of such waves presented by N. Kaloper in [Phys.Rev.D114(2026)L051903] and show that at an intermediate step certain terms were missed in an equation therein. Taking these terms into account changes the final conclusion of [Phys.Rev.D114(2026)L051903]. We also show that the method used in [arXiv:2606.12513 [hep-th]] to reproduce the same result is not consistent.
↳ hep-thastro-ph.COhep-phphysics.optics+1
19
Stars Would Remember a Recent Gravitational Transition: Testing G-step Resolutions of the Hubble Tension with Red Dwarfs
Jeremy Sakstein · Harry Desmond
We test the hypothesis that Newton's gravitational constant underwent a rapid transition approximately $73$ - $130 Myr$ ago, as proposed in some resolutions of the Hubble tension. Fully convective red dwarf stars with masses below $\sim 0.35 M_{⊙}$ have thermal timescales comparable to the proposed transition look-back times, so an appreciable present-day memory can remain. We show that a rapid step in $G$ induces measurable changes in their radii and confront these predictions with mass-radius measurements of eight red dwarfs in detached eclipsing binaries. We find that the $G$ -step models proposed to resolve the Hubble tension, corresponding to a $4%$ change in $G$ at a look-back time of $73 Myr$ and an $11%$ change at $130 Myr$ , are excluded at significances of $3.1 σ$ and $4.0 σ$ , respectively.
↳ astro-ph.COastro-ph.GAastro-ph.SRgr-qc+1
20
Dark matter in neutron stars: two-fluid $f$ -mode oscillations in full general relativity
Prashant Thakur · Ishfaq Ahmad Rather · Y. Lim
A dark-matter core and a soft nuclear equation of state can produce similar mass--radius signatures, motivating a complementary probe through the $f$ -mode spectrum. We compute quadrupolar $f$ -mode frequencies and gravitational-wave damping times in full general relativity for cold, nonrotating neutron stars admixed with self-interacting bosonic dark matter (DM). Our two-fluid survey spans 21 nuclear equations of state covering nucleonic, hyperonic, $Δ$ -admixed, and combined hyperon-- $Δ$ compositions at $F_{DM} = 1$ -- $20%$ . The main sequences use $λ = π$ and boson masses of $500$ and $100 MeV$ for the core and halo studies, respectively. Independent normal-matter (NM) and DM displacements couple through the metric, yielding NM-led and DM-led $f$ -mode branches whose radiative damping is determined by outgoing-wave boundary conditions. At $1.4 M_{⊙}$ , the core DM-led damping time decreases from order $1 0^{3} s$ at $F_{DM} = 1%$ to order $1 s$ at $20%$ , approximately following an empirical $F_{DM}^{- 2}$ dependence, while NM-led damping times remain within $0.12$ -- $0.33 s$ . Halo DM-led damping instead increases with dark fraction: at the same stellar mass and $F_{DM} = 20%$ , dark radii approach $88 km$ , frequencies fall to $0.14 kHz$ , and damping times reach approximately $450 s$ . Selected high-mass core sequences exhibit strong DM-led damping-time upturns not reproduced by the leading mass-quadrupole diagnostic. Representative core calculations show greater DM-led sensitivity to the bosonic self-coupling and retain both branches at $ℓ = 3$ . Under the adopted nonrotating, circular-binary prescriptions, no evaluated configuration satisfies all geometric and perturbative conditions for a controlled linear tidal resonance.
↳ astro-ph.HEhep-ph
21
Particle emission from $^{40}$ Ar nuclei excited in fixed-target $^{208}$ Pb+ $^{40}$ Ar UPC at the LH
P. Jucha · M. Klusek-Gawenda · K. Mazurek · L. L. Pappalardo · K. Pysz · A. Szczurek
Ultraperipheral collisions of heavy ions, dominated by the electromagnetic interaction, allow to investigate the photoproduction of baryons and mesons from the excited nuclei. At LHCb, thanks to the SMOG2 system, these studies can also be conducted in fixed-target collisions, exploiting a variety of target gases ranging from $^{4}$ He to Xe. In the present work, we adapted our photonuclear model and the Giesen-Boltzmann-Uehling-Uhlenbeck (GiBUU) generator to study photoproduction of protons, neutrons as well as pions and kaons from excited $^{40}$ Ar nuclei in fixed-target ultraperipheral collisions with the LHC $^{208}$ Pb beam. We present predictions for the total and differential photoproduction cross sections in $p$ and $p_{T}$ , both in the full phase-space and within the geometrical acceptance of the LHCb detector.
↳ nucl-exhep-ph