Abstract The SND@LHC experiment is currently taking data at the Large Hadron Collider (LHC), exploring the unique forward region at pseudorapidities $$7.2<\eta <8.4$$ 7.2 < η < 8.4 . Its physics programme covers neutrinos originating from heavy-flavour decays and feebly interacting particles produced in proton–proton collisions. Building upon the successful operation of the present detector, this paper presents the physics reach of the approved SND@LHC upgrade for Run 4 of the LHC, and compares it with an alternative installation scenario. Lowering the detector by approximately 40 cm and shifting it horizontally by about 30 cm, while keeping it off-axis, increases the total neutrino interaction rate by a factor of five. The paper describes the design of the upgraded detector and compares the physics performance in both installation scenarios.
Abstract In the present work, we propose to investigate the productions of $$P_{c}(4312)$$ P c ( 4312 ) , $$P_{c}(4440)$$ P c ( 4440 ) , and $$P_{c}(4457)$$ P c ( 4457 ) in the $$e^{+} e^{-} \rightarrow p \bar{p} J/\psi $$ e + e - → p p ¯ J / ψ process by utilizing an effective Lagrangian approach, where $$P_{c}(4312)$$ P c ( 4312 ) is considered as $$\Sigma _{c} \bar{D}$$ Σ c D ¯ molecular state with $$J^{P}=1/2^{-}$$ J P = 1 / 2 - , while $$P_{c}(4440)$$ P c ( 4440 ) and $$P_{c}(4457)$$ P c ( 4457 ) are considered as $$\Sigma _{c} \bar{D}^{*}$$ Σ c D ¯ ∗ molecular states with $$J^{P}=1/2^{-}$$ J P = 1 / 2 - and $$J^{P}=3/2^{-}$$ J P = 3 / 2 - , respectively. For the $$e^{+} e^{-} \rightarrow \bar{p} P_{c}(4312)$$ e + e - → p ¯ P c ( 4312 ) , $$e^{+} e^{-} \rightarrow \bar{p} P_{c}(4440)$$ e + e - → p ¯ P c ( 4440 ) , and $$e^{+} e^{-} \rightarrow \bar{p} P_{c}(4457)$$ e + e - → p ¯ P c ( 4457 ) processes, the cross sections are evaluated to be ( $$27.8^{+42.2}_{-17.9}$$ 27 . 8 - 17.9 + 42.2 ) fb, ( $$38.7^{+58.6}_{-25.1}$$ 38 . 7 - 25.1 + 58.6 ) fb, and ( $$1.44^{+2.18}_{-0.93}$$ 1 . 44 - 0.93 + 2.18 ) fb at $$\sqrt{s}=6$$ s = 6 GeV, respectively, where the central values are estimated with $$\Lambda _{r}=2.5$$ Λ r = 2.5 GeV, and the uncertainties are resulted from the variations of $$\Lambda _{r}$$ Λ r from 2.0 to 3.0 GeV. Considering that the $$P_{c}$$ P c states can decay into $$J/\psi p$$ J / ψ p , we estimate the cross sections for $$e^{+} e^{-} \rightarrow p \bar{p} J/\psi $$ e + e - → p p ¯ J / ψ and the differential cross sections depending on the $$J/\psi p$$ J / ψ p invariant mass. At $$\sqrt{s}=6$$ s = 6 GeV, the cross sections for $$e^{+} e^{-} \rightarrow p \bar{p} J/\psi $$ e + e - → p p ¯ J / ψ are estimated to be ( $$14.7^{+22.2}_{-9.50}$$ 14 . 7 - 9.50 + 22.2 ) fb. Moreover, our estimations indicate that the cross section resulted from the $$P_{c}(4440)$$ P c ( 4440 ) and $$\bar{P}_{c}(4440)$$ P ¯ c ( 4440 ) intermediate states is dominant. In the $$J/\psi p$$ J / ψ p invariant mass spectrum, our estimations reveal that the peak structure between 4.42 and 4.46 GeV primarily originates from $$P_{c}(4440)$$ P c ( 4440 ) .
Abstract We revisit the constrained log-subtracted two-point Padé (LSTP) ensemble for thermal $$\mathcal {N}{=}4$$ N = 4 supersymmetric Yang-Mills (SYM) thermodynamics in four spacetime dimensions after upgrading the weak-coupling truncation from $$\mathcal {O}(\lambda ^2)$$ O ( λ 2 ) to the exact $$\mathcal {O}(\lambda ^{5/2})$$ O ( λ 5 / 2 ) coefficient. We keep the LSTP interpolation ansatz unchanged and shift the weak-side matching points to the regime where the new term is numerically significant. Within the same parameter scan the admissible set collapses from 9 nominal survivors (3 distinct curves) to a single distinct curve, the crossover range shrinks to a unique value, and the pointwise band width drops to zero within numerical resolution. The Hermite-Padé (HP) central curve does not coincide with the unique LSTP survivor, so the updated weak-side matching removes the LSTP scan uncertainty but not the difference between the two routes. The minimal HP extension that also carries the exact coefficient is uniquely determined and develops a spurious pole-zero pair at small coupling. Away from that pair the HP and LSTP curves still differ, so this difference persists at the same weak-coupling order.
Abstract Anomalies in the non-leptonic $$\bar{B}^0\rightarrow D^{(*)+}K^{(*)-}$$ B ¯ 0 → D ( ∗ ) + K ( ∗ ) - and $$\bar{B}^0_s\rightarrow D^{(*)+}_s\pi ^-$$ B ¯ s 0 → D s ( ∗ ) + π - decays may be an indication of physics beyond the Standard Model, but the large deviations require strongly coupled new physics that should be visible at colliders. We explore three new directions that could lead to viable new physics models, performing a detailed collider study to examine the possible weakening of previously known constraints on additional $$SU(2)_L$$ S U ( 2 ) L doublets. Our results show that, despite the difficulty of probing $$t\bar{t}$$ t t ¯ final states, increasing the branching ratio to this decay mode does not significantly weaken the bounds on weak doublet scalars, as additionally existing charged Higgs searches are equally strong. Beyond this, we analyse a potentially large breakdown of QCD factorisation by including large-power corrections to B decays, and the effect of diluting collider searches with multi-scalar extensions. We find that these typical model-building routes for constructing a viable scenario remain constrained by collider measurements, indicating that these non-leptonic anomalies remain among the most puzzling discrepancies from the SM.
Abstract In the present work, we propose to investigate the productions of $$P_{c}(4312)$$ P c ( 4312 ) , $$P_{c}(4440)$$ P c ( 4440 ) , and $$P_{c}(4457)$$ P c ( 4457 ) in the $$e^{+} e^{-} \rightarrow p \bar{p} J/\psi $$ e + e - → p p ¯ J / ψ process by utilizing an effective Lagrangian approach, where $$P_{c}(4312)$$ P c ( 4312 ) is considered as $$\Sigma _{c} \bar{D}$$ Σ c D ¯ molecular state with $$J^{P}=1/2^{-}$$ J P = 1 / 2 - , while $$P_{c}(4440)$$ P c ( 4440 ) and $$P_{c}(4457)$$ P c ( 4457 ) are considered as $$\Sigma _{c} \bar{D}^{*}$$ Σ c D ¯ ∗ molecular states with $$J^{P}=1/2^{-}$$ J P = 1 / 2 - and $$J^{P}=3/2^{-}$$ J P = 3 / 2 - , respectively. For the $$e^{+} e^{-} \rightarrow \bar{p} P_{c}(4312)$$ e + e - → p ¯ P c ( 4312 ) , $$e^{+} e^{-} \rightarrow \bar{p} P_{c}(4440)$$ e + e - → p ¯ P c ( 4440 ) , and $$e^{+} e^{-} \rightarrow \bar{p} P_{c}(4457)$$ e + e - → p ¯ P c ( 4457 ) processes, the cross sections are evaluated to be ( $$27.8^{+42.2}_{-17.9}$$ 27 . 8 - 17.9 + 42.2 ) fb, ( $$38.7^{+58.6}_{-25.1}$$ 38 . 7 - 25.1 + 58.6 ) fb, and ( $$1.44^{+2.18}_{-0.93}$$ 1 . 44 - 0.93 + 2.18 ) fb at $$\sqrt{s}=6$$ s = 6 GeV, respectively, where the central values are estimated with $$\Lambda _{r}=2.5$$ Λ r = 2.5 GeV, and the uncertainties are resulted from the variations of $$\Lambda _{r}$$ Λ r from 2.0 to 3.0 GeV. Considering that the $$P_{c}$$ P c states can decay into $$J/\psi p$$ J / ψ p , we estimate the cross sections for $$e^{+} e^{-} \rightarrow p \bar{p} J/\psi $$ e + e - → p p ¯ J / ψ and the differential cross sections depending on the $$J/\psi p$$ J / ψ p invariant mass. At $$\sqrt{s}=6$$ s = 6 GeV, the cross sections for $$e^{+} e^{-} \rightarrow p \bar{p} J/\psi $$ e + e - → p p ¯ J / ψ are estimated to be ( $$14.7^{+22.2}_{-9.50}$$ 14 . 7 - 9.50 + 22.2 ) fb. Moreover, our estimations indicate that the cross section resulted from the $$P_{c}(4440)$$ P c ( 4440 ) and $$\bar{P}_{c}(4440)$$ P ¯ c ( 4440 ) intermediate states is dominant. In the $$J/\psi p$$ J / ψ p invariant mass spectrum, our estimations reveal that the peak structure between 4.42 and 4.46 GeV primarily originates from $$P_{c}(4440)$$ P c ( 4440 ) .
New constraints on Cartan torsion components are obtained from the teleparallel equivalent of General Relativity (TEGR) repulsive gravity with global textures. The interior solution is considered a global texture fulfilling Einstein gravity, whereas the exterior solution is a spherical symmetric vacuum. The torsion components are constrained from the matching condition in Einstein–Cartan gravity given by, where the interior solution is an Einstein gravity global texture and the exterior solution is a flat spacetime in spherical coordinates. We show that one of the components of torsion trace T^2_12<<10^-44 GeV, which is much more stringent than the estimate of 10^-31 GeV by Kostelecky et al. (PRL(2008)) for the torsion Lorentz violation and in dual maser. To compute this bound we use the texture correlation length as the inverse of the Hubble constant and the texture tachyonic and small-angle approximations. Another method for placing bounds on torsion is to use teleparallel gravitational waves (GW). These bounds are based on LIGO data.
Abstract We revisit the constrained log-subtracted two-point Padé (LSTP) ensemble for thermal $$\mathcal {N}{=}4$$ N = 4 supersymmetric Yang-Mills (SYM) thermodynamics in four spacetime dimensions after upgrading the weak-coupling truncation from $$\mathcal {O}(\lambda ^2)$$ O ( λ 2 ) to the exact $$\mathcal {O}(\lambda ^{5/2})$$ O ( λ 5 / 2 ) coefficient. We keep the LSTP interpolation ansatz unchanged and shift the weak-side matching points to the regime where the new term is numerically significant. Within the same parameter scan the admissible set collapses from 9 nominal survivors (3 distinct curves) to a single distinct curve, the crossover range shrinks to a unique value, and the pointwise band width drops to zero within numerical resolution. The Hermite-Padé (HP) central curve does not coincide with the unique LSTP survivor, so the updated weak-side matching removes the LSTP scan uncertainty but not the difference between the two routes. The minimal HP extension that also carries the exact coefficient is uniquely determined and develops a spurious pole-zero pair at small coupling. Away from that pair the HP and LSTP curves still differ, so this difference persists at the same weak-coupling order.
Abstract The Future Circular Collider (FCC) stands at the forefront of the European Strategy for Particle Physics as the future flagship project at CERN. The H $$\rightarrow \tau \tau $$ → τ τ decay, featuring a large branching ratio, clean identification in the FCC-ee environment, and the possibility to reconstruct tau spin-related observables, is an excellent channel to measure Higgs boson properties. This work shows the expected precision for the H $$\rightarrow \tau \tau $$ → τ τ cross-section measurement at the FCC-ee in the ZH production mechanism at $$\sqrt{s}=$$ s = 240 GeV and $$\sqrt{s}=$$ s = 365 GeV, as well as via the vector boson fusion process at $$\sqrt{s}=$$ s = 365 GeV. Furthermore, we explore and evaluate a set of methods for reconstructing tau decays. These techniques are critical for unlocking the full physics potential of the FCC-ee and for improving the understanding of tau-related observables in both Standard Model measurements and New Physics searches. The obtained results significantly enhance the FCC-ee outlook in the H $$\rightarrow \tau \tau $$ → τ τ channel, improving it by at least an order of magnitude compared to the current uncertainties on the cross-sections measured at the LHC.
Abstract In this work, we construct an $$A_4$$ A 4 -based flavor symmetry model within the framework of the type-I seesaw mechanism to realize a light neutrino mass matrix consistent with $$\mu $$ μ – $$\tau $$ τ reflection symmetry. The entire framework is based on the Standard Model gauge symmetry extended by the discrete group $$A_4 \times Z_2 \times Z_4$$ A 4 × Z 2 × Z 4 . In general, the elements of the light Majorana neutrino mass matrix are complex. The $$\mu $$ μ – $$\tau $$ τ reflection symmetric texture of the mass matrix can be realized in a generalized CP symmetry limit. In this symmetry limit, the model predicts a maximal atmospheric mixing angle $$\theta _{23} = \pi /4$$ θ 23 = π / 4 and a maximal Dirac CP phase $$\delta = (\pi /2) / (3\pi /2)$$ δ = ( π / 2 ) / ( 3 π / 2 ) . These features are consistent with current experimental observations, including a near-maximal value of $$\theta _{23}$$ θ 23 , a non-zero $$\theta _{13}$$ θ 13 , and a preference for $$\delta $$ δ close to $$270^\circ $$ 270 ∘ , as indicated by the T2K and NO $$\nu $$ ν A experiments. Non-maximal values of $$\theta _{23}$$ θ 23 and $$\delta $$ δ can be accommodated when one does not restrict to the CP symmetry limit. The model predictions for the mixing angles and the Dirac CP phase $$\delta $$ δ are then controlled by two model parameters. We perform a numerical analysis to identify the allowed model parameter values consistent with current global $$3\nu $$ 3 ν oscillation data. The model successfully reproduces the observed deviations of $$\theta _{23}$$ θ 23 and $$\delta $$ δ from their maximal values, while accommodating the observed values of $$\theta _{12}$$ θ 12 and $$\theta _{13}$$ θ 13 , consistent with current global fit data. We also study the charged lepton flavor violating decays $$\mu \rightarrow e\gamma $$ μ → e γ and $$\mu \rightarrow 3e$$ μ → 3 e , whose predicted branching ratios satisfy current experimental bounds.
Abstract We study the local horizon residue and minimally coupled massless-scalar quasinormal modes of the logarithmic connection-hair background obtained perturbatively in the quadratic model $$f(Q)=Q+\alpha Q^2$$ f ( Q ) = Q + α Q 2 . After mass renormalization the displayed order- $$\alpha ^2$$ α 2 blackening function is $$F(r)=1-[2M+\eta \ln (r/r_\star )]/r$$ F ( r ) = 1 - [ 2 M + η ln ( r / r ⋆ ) ] / r , with $$\eta =\alpha ^2\mu $$ η = α 2 μ . Euclidean regularity and the simple pole of 1/ F give the same Hawking temperature, while the same residue multiplies the near-horizon logarithm of the scalar tortoise coordinate. We derive the massless-scalar master equation, its effective potential, the photon-sphere equation, and the controlled first-order shifts of the eikonal scalar frequency and damping rate. We do not identify the integration parameter M with a Hamiltonian or Noether mass: the logarithmic tail leaves the perturbative regime at large radius and does not satisfy the standard falloff required for a finite ADM charge. Consequently no physical entropy, heat capacity, Ruppeiner metric, or gravitational quasinormal-mode spectrum is claimed. For comparison only, we retain an explicitly labelled auxiliary Hessian construction and an algebraic evaluation of the resummed truncated metric at $$r_h=2\eta $$ r h = 2 η . That point has $$|\eta |/r_h=1/2$$ | η | / r h = 1 / 2 and is therefore outside perturbative control; its finite scalar null-orbit and WKB frequencies are properties of the truncated function, not predictions of quadratic f ( Q ) gravity. The controlled result is the local temperature–scalar-monodromy residue identity and the distinct small-hair shifts sampled at the horizon and photon sphere.
Abstract We developed a unified framework based on a special (non-regular) embedding of the exceptional group $$E_6$$ E 6 in which the main stage of symmetry breaking chain realizes $$E_6\rightarrow G(2) \times SU(3)_A$$ E 6 → G ( 2 ) × S U ( 3 ) A . The exceptional factor G (2) plays the role of a hidden strong sector, while $$SU(3)_A$$ S U ( 3 ) A acts as an ancestor of the electroweak gauge group. A minimal scalar sector is organized around a $$\textbf{650}$$ 650 -based $$E_6$$ E 6 Higgs sector. Its $$G(2)\times SU(3)_A$$ G ( 2 ) × S U ( 3 ) A components $$(\textbf{7},\textbf{1})$$ ( 7 , 1 ) and $$(\textbf{1},\textbf{8})$$ ( 1 , 8 ) implement the subsequent breaking steps $$G(2)\rightarrow SU(3)_C$$ G ( 2 ) → S U ( 3 ) C and $$SU(3)_A\rightarrow SU(2)_L\times U(1)_A$$ S U ( 3 ) A → S U ( 2 ) L × U ( 1 ) A . The speciality of this symmetry breaking establishes the feature of darkness . Defining a hypercharge from the $$t_{8}$$ t 8 generator of $$SU(3)_A$$ S U ( 3 ) A is not sufficient to recover the exact Standard Model hypercharges and the correct Weinberg weak angle, leading to the necessity of an $$E_7$$ E 7 uplift which introduces only a proper additional $$U(1)_X$$ U ( 1 ) X factor to fix the abelian sector. The special embedding naturally suppresses tree-level leptoquark couplings that typically mediate proton decay in regular grand unified theories. The scalar potential for the Higgs sectors has been constructed, deriving the heavy gauge-bosons spectrum and presenting a consistent one-loop running of the gauge couplings across the intermediate scales, which is shown to satisfy an $$E_6$$ E 6 unification. The exotic states are organized in $$E_7$$ E 7 -derived vectorlike pairs and are made ultraheavy, while a chirality-selecting projection keeps only the desired Standard Model zero modes. All non-Standard Model Higgs fields and broken massive vectors are found to be invisible to colliders searches. The G (2) gluons ensemble confines into heavy dark glueballs with parametrically suppressed communication with $$SU(3)_A$$ S U ( 3 ) A and $$U(1)_X$$ U ( 1 ) X sectors. Cosmological history is analyzed in details, including topological defects, inflation and reheating, demonstrating that monopole relics are naturally diluted. The resulting framework provides a minimal and internally consistent exceptional apparatus which includes the Standard Model and a dark matter sector which is secluded by the group-theoretic orthogonality.
Abstract The SND@LHC experiment investigates neutrinos in the $$7.2< \eta < 8.4$$ 7.2 < η < 8.4 forward pseudorapidity range. The detector consists of a veto system, a scintillating fiber tracker interleaved with emulsion cloud chambers, and a downstream muon system. Muons originating from collisions at ATLAS (IP1) constitute the primary background for CC neutrino interactions and determine the replacement frequency of the emulsion target. A precise characterization of this flux is therefore essential. In this work, we report the muon flux measured in the central $$31 \times 31$$ 31 × 31 $$\textrm{cm}^2$$ cm 2 fiducial area of the detector using data from 2023 through 2025. The measured fluxes for proton collisions are: (1.90±0.04) $$\times 10^{-2}$$ × 10 - 2 $$\text {nb/cm}^{2}$$ nb/cm 2 (2023), (3.76 ± 0.09) $$\times $$ × $$\text {10}^{-2}$$ 10 - 2 $$\text {nb/cm}^{2}$$ nb/cm 2 (2024), and (2.48 ± 0.05) $$\times 10^{-2}$$ × 10 - 2 $$\text {nb/cm}^{2}$$ nb/cm 2 (2025). A 2024 reference proton run at $$\sqrt{s} = 5.36\text { TeV}$$ s = 5.36 TeV yielded (4.21 ± 0.14) $$\times $$ × $$\text {10}^{-2}$$ 10 - 2 $$\text {nb/cm}^{2}$$ nb/cm 2 , providing a direct baseline for the heavy-ion energy regime. The measured fluxes for heavy-ion collisions are (3.11±0.12) $$\times \text {10}^{4}$$ × 10 4 $$\text {nb/cm}^{2}$$ nb/cm 2 , (5.53±0.22) $$\times 10^{4}$$ × 10 4 $$\text {nb/cm}^{2}$$ nb/cm 2 , and (3.24±0.13) $$\times \text {10}^{4}$$ × 10 4 $$\text {nb/cm}^{2}$$ nb/cm 2 in 2023, 2024, and 2025, respectively. Uncertainties are dominated by systematic effects, with the statistical component contributing $$\lesssim $$ ≲ 0.1% to the total uncertainty. These results are in agreement with Monte Carlo predictions.
Explicit diffeomorphism breaking in gravitational theories with nondynamical background fields is constrained by the compatibility between the modified Einstein equations and the contracted Bianchi identities. We implement an isometry-based approach in which the background fields are required to be invariant under the Killing symmetries of the spacetime. Applying this construction to the Gödel geometry, we determine the most general form-invariant scalar, symmetric rank-two, and Riemann-like rank-four background tensors and analyze the corresponding modified gravitational field equations. We show that the resulting configurations satisfy the required consistency conditions and derive the associated Noether identities in the presence of nondynamical backgrounds. The background coefficients modify the relations among the cosmological constant, the matter density, and the Gödel rotation parameter while preserving the Gödel metric as an exact solution. We also determine the corresponding critical radius for closed timelike curves and examine how the background fields modify the boundary between the causal and noncausal regions of the spacetime.
We investigate the thermodynamic behaviour of an AdS black hole arising from nonlinear electrodynamics-corrected gravity, incorporating quantum effects through thermal fluctuations. From the Einstein–Euler–Heisenberg framework, we consider the modified black hole solution and analyse its thermodynamic properties in the extended phase space. Logarithmic and inverse-area corrections to the entropy are obtained, leading to modified expressions for enthalpy, internal energy, Helmholtz free energy and Gibbs free energy. The corrected specific heat exhibits multiple divergences and sign changes, signalling genuine second-order phase transitions and revealing a quantum-stabilized microscopic phase followed by universal macroscopic instability. Our results demonstrate that thermal fluctuations qualitatively restructure the thermodynamic phase space and highlight the dominant role of quantum corrections in governing the black hole stability.
This study investigates how dark matter in the background of the phantom field (DMPF) near a black hole influences neutrino flavor oscillations using a two-flavor model. It is found that gravitational effects are cancelled for radially moving neutrinos, causing the oscillation phase to increase with distance and mass-splitting, similar to flat spacetime. However, deflected neutrinos experience additional phase shifts due to dark matter, which slightly alters the mass-difference term and the total phase. Numerical analysis supports these findings and reveals a degeneracy between lens mass and dark matter parameters, affecting the transition probability curves based on source angle changes. Neutrinos modeled as Gaussian wave packets show that decoherence in a gravitational field is minimally influenced by dark matter, with the absolute neutrino mass determining the oscillation duration. Our findings imply that curved spacetime and dark matter significantly impact neutrino oscillations, offering potential insights into dark matter through neutrino astronomy in extreme environments.
Abstract The KNO-violating term $$f_s$$ f s of the charged-particle multiplicity distribution in pp collisions measures the relative deviation of $$\langle n\rangle P_n$$ ⟨ n ⟩ P n from $$e^{-z}$$ e - z , with $$z=n/\langle n\rangle $$ z = n / ⟨ n ⟩ , and is reported to obey the reciprocal symmetry $$f_s(z)=f_s(1/z)$$ f s ( z ) = f s ( 1 / z ) , taken here as input. Being an evenness condition in $$\ln z$$ ln z , it generates a tower of local constraints on the derivatives of $$P_n$$ P n at the mean. The lowest member holds for the ATLAS data at 7, 8 and 13 TeV at the few-per-cent level, while the third-derivative residual testing the next member is not determined with a controlled uncertainty by the present binning and stays inconclusive. The global test is consistent at 7 and 8 TeV, while at 13 TeV a residual deviation remains, which a closure test shows is not a binning artefact. Multiplicative noise in the Mueller colour-dipole cascade, the negative binomial and the dipole cascades with recombination each give an $$f_s$$ f s that is not invariant under $$z\rightarrow 1/z$$ z → 1 / z , so none of them carries the symmetry. We further obtain a dynamics-independent entropy in the KNO continuum, $$S=\ln \langle n\rangle +I_0-\tfrac{1}{2}\int e^{-z}f_s^2\,dz$$ S = ln ⟨ n ⟩ + I 0 - 1 2 ∫ e - z f s 2 d z , with $$I_0$$ I 0 a support factor tending to unity in the continuum limit. The linear term cancels by normalisation and unit mean, independently of the symmetry, and the remaining correction is quadratic and negative. It reproduces the Shannon entropy of the ATLAS data at the $$10^{-3}$$ 10 - 3 level.
Abstract The presence of $$\alpha $$ α clustered structures in light nuclei can enhance the initial spatial anisotropies in relativistic nuclear collisions relative to those arising from nuclei with uniform density distributions. Thus, observables that are strongly sensitive to the initial geometry can be a more efficient probe of the clustered structures than observables dominated by final state dynamics. We investigate the collisions of $$\alpha $$ α clustered oxygen nuclei at $$\sqrt{s_{NN}}=7$$ s NN = 7 A TeV at the LHC using the GLISSANDO initial state model along with the MUSIC event-by-event hydrodynamical framework. The tetrahedral $$\alpha $$ α clustered structure of $$^{16}$$ 16 O leads to significantly larger initial triangular eccentricity $$\epsilon _3$$ ϵ 3 than collisions with uniform density distributions especially in the most central events. The spatial eccentricity $$\epsilon _2$$ ϵ 2 is found to be relatively less sensitive to the initial state clustered structure. The production of thermal photons is estimated to be only marginally influenced by clustering for both central as well as peripheral collisions. In contrast, the photon triangular flow coefficient $$v_3(p_T)$$ v 3 ( p T ) is strongly affected by initial state clustering resulting in substantially larger values in both central and peripheral collisions. An experimental determination of photon anisotropic flow together with the ratios of flow coefficients in $$^{16}$$ 16 O+ $$^{16}$$ 16 O collisions therefore expected to provide valuable insight into the possible clustered structure in light nuclei and also to constrain parameters in theoretical modeling.
Abstract In this article, we investigate the observational properties of the Reissner–Nordstr $$\ddot{\textrm{o}}$$ o ¨ m–Tangherlini (RNT) black hole (BH). Firstly, we briefly explore the spacetime properties of the RNT BH, including the horizon structure and scalar invariants. It was found that the values of the event horizon radius decrease with increasing BH dimension and charge. Subsequently, we explore the massive and massless particle dynamics around RNT BH. Afterwards, gravitational weak lensing is investigated for two plasma types: uniform and non-uniform. Our results show that a uniform plasma increases the deflection angle of light around an RNT BH, whereas a non-uniform plasma decreases it. Finally, we study the BH shadow and constrain the values of the spacetime parameters using the Event Horizon Telescope (EHT) observational results.
