We present an analytical investigation of the creation of neutral scalar particle–antiparticle pair in the spacetime of a cosmic string under the combined influence of Coulomb-type interactions and a KG-oscillator–type nonminimal coupling. The scalar field is described by a modified Klein–Gordon equation including scalar, minimally coupled vector, and nonminimally coupled vector interactions. Exact solutions for the field modes are obtained, allowing the Bogoliubov coefficients, particle production probability, and number density to be derived explicitly. Our analysis reveals that the nontrivial topology of the cosmic string spacetime, together with the confining effect of the KG-oscillator–type nonminimal coupling, plays a crucial role in enhancing vacuum instability. We show that Coulomb-type interactions introduce an additional control mechanism that can significantly amplify particle creation, even in regimes where minimal coupling alone does not lead to vacuum decay. The dependence of the production rate on the cosmic string parameter and the quantum numbers is analyzed in detail. These results provide a unified analytical framework for understanding scalar pair creation in topologically nontrivial spacetimes and may be relevant to early-universe particle generation as well as analogue gravity systems.
The concept of self-similarity in the internal structure of the proton, rooted in scale invariance and fractal geometry, provides an intriguing framework for understanding the behaviour of parton distribution functions (PDFs), particularly in the small x region probed in deep inelastic scattering (DIS). Phenomenological models based on self-similarity have been shown to reproduce key features of experimental data, suggesting that recursive scaling patterns may play an important role in partonic dynamics. In this work, we present an overview of scale-invariant descriptions of proton structure, focusing on self-similar models developed in earlier studies and their phenomenological implications for structure functions and parton distributions. We then explore possible conceptual connections between these fractal-inspired descriptions and modern holographic approaches to QCD, particularly within the framework of light-front holographic QCD. By comparing the scaling behaviour appearing in phenomenological models with the geometric structure underlying holographic QCD, we highlight qualitative correspondences that suggest a broader role of scale invariance in proton structure. Although the connection remains interpretive rather than derivational, it offers a complementary perspective of how fractal-like scaling observed in DIS may relate to geometric scaling in holographic descriptions of QCD.
We investigate the phenomenological consequences of a dimension-6 operator H dagger H3/Lambda 2, Lambda is the effective scale at which new physics takes over, which modifies the scalar potential of the standard model and can induce a strong first-order electroweak phase transition (SFOEWPT). We estimate the lower limit on the effective scale Lambda to be 515 GeV from the di-Higgs production cross section measured by the LHC. We analyze the associated collider and cosmological signatures in a unified framework, emphasizing the complementarity between gravitational wave (GW) observations and multi-Higgs production at hadron colliders. Using one-loop and finite-temperature effective potential techniques, we identify the parameter space where SFOEWPT occurs and compute the resulting stochastic GW spectra. We show that for cutoff scales Lambda less than or similar to 750 GeV, the predicted GW signal lies within the sensitivity reach of future interferometers such as LISA, DECIGO, and BBO. At the same time, such low-scale scenarios also enhance di-Higgs and tri-Higgs production cross sections, making them testable at the HL-LHC, HE-LHC, and FCC-hh. We derive current bounds on Lambda from Run-II di-Higgs searches and demonstrate how future multi-Higgs measurements can probe the same region favored by GW observability. Our results highlight the power of combining collider and GW experiments to probe extended scalar interactions and the nature of electroweak symmetry breaking.
In this paper, we presented an approximate analytical treatment of the Coulomb plus logarithmic potential using perturbation theory to investigate the mass spectra of bottomonium and charmonium mesons for the low-order quantum states. The derived energy equation, to first-order corrections, was employed to model the free potential parameters through fitting to experimental data of the Particle Data Group. The proposed potential successfully reproduces asymptotic freedom at short distances through one-gluon exchange interactions and quark confinement at large distances, which are the essential features of the strong interactions in Quantum chromodynamics theory. The calculated bottomonium masses exhibited excellent agreement with experimental values, yielding an absolute percentage average deviation (APAD) of 0.24
In this work, the radial Schrodinger equation with a nonrelativistic quark potential model (NRQPM) is solved numerically by employing the shooting method. Calculated numerical wave functions (or solutions) are used to compute the masses, root mean square (RMS) radii, E1, M1 radiative transition widths, annihilation decay widths, and branching ratios of S, P, D, and F states of toponium tt & strns;. Calculated results are compared with recently available theoretical data. This work will be helpful for experimentalists in gaining a deeper understanding of quasibound toponium states.
In this work, a renormalizable neutrino mass model based on (Z2 & times; Z4)& rtimes;Z2 (II) symmetry is proposed for the modification of the mu - tau reflection symmetry. The hierarchies of lepton masses can be naturally realized, and the lepton mixing is addressed. The predicted intervals of the sum of neutrino mass and the Majorana effective neutrino mass are consistent with the corresponding experimental limits.
In this work, we present an analytical description of the energy distributions of primary and secondary cosmogenic particles on Earth in terms of parameters having clear physical meaning. A modified power law is assumed for energy distributions, incorporating terms such as energy loss/decay, which are effective at low energies, and a source term, which is dominant at high energies. The parametrizations of the momentum distribution of primary protons and helium have been obtained including energy loss term. For muons, both the energy loss and decay terms have been included. It is shown analytically that zenith angle distributions is given by cosn-1 theta in terms of energy index n and the presence of decay term does not affect it. The analytical function describes the muon momentum distribution data at different altitudes and zenith angles. The same form is also applied to describe the atmospheric muon and electron-type neutrino distributions simulated at various sites. The presented analytical functions provide an excellent description of all kinds of cosmogenic particles.
With the potential prospects of the Ds & lowast; at high-luminosity heavy-flavor experiments in the future, we investigated the CKM-favored and tree-dominated leptonic Ds & lowast;->& ell;nu & strns;& ell;,& ell;=e,mu,tau and semileptonic Ds & lowast;-> M & ell;'nu & strns;& ell;' M=phi,eta ',K and & ell;'=e,mu weak decays in the standard model (SM). The theoretical predictions and some discussions for the observable quantities including the total width of Ds & lowast; mesons, the branching fractions of leptonic Ds & lowast;->& ell;nu & strns;& ell; and semileptonic Ds & lowast;-> M & ell;'nu & strns;& ell;' weak decays, the lepton spin asymmetry, and forward-backward asymmetry are presented. Numerically, the weak decays of Ds & lowast;->& ell;nu & strns;& ell; and Ds & lowast;-> M & ell;'nu & strns;& ell;' have relatively large branching fractions of the order O10-5 and O10-8, respectively, which are expected to be observed in future experiments.
The neutrino transition magnetic moment μ_ν_αβ is studied in a simple extension of the Standard Model. This extension incorporates two scalar Leptoquarks S_1 and R_2 with quantum numbers (3̅,1,1/3) and (3,2,1/6) respectively. It is found that these Leptoquarks generate a sizable transition magnetic moment, particularly when the quark bottom is running in the loop. For our analysis of the parameter space, we include the latest measurement of the muon magnetic moment and combine it with the experimental constraint on the branching ratio Br(τ→ μγ). We found that, despite the recent agreement on the (g-2)_μ value, large values for Leptoquark Yukawa couplings are allowed due to a degeneracy in the parameters. Additionally, we explore how the Leptoquark model address the anomalies observed in the ratios of semileptonic B mesons decays, R_D^(*). We determine that the restrictions derived from our analysis are consistent with the most recent experimental limits reported by the XENONnT and LUX-ZEPLIN collaborations. This conclusion is based on our evaluation of the transition magnetic moment from muon neutrino to tau neutrino, focusing on the allowed region for the Leptoquark Yukawa couplings.
The effective string tension (kappa) in the Schwinger mechanism and the effective temperature (T) in Bose-Einstein statistics are extracted from the transverse momentum (pT) spectra of heavy quarkonia produced in proton-proton (p + p) collisions at the Large Hadron Collider (LHC). Here, T derived from the heavy quarkonium pT spectra also serves as the initial effective temperature (effective temperature at the initial stage) of small collision systems. This is because, despite the absence of quark-gluon plasma (QGP) formation during the collisions, which leaves T largely unaffected by QGP-related effects, the initial geometric asymmetry and local partonic thermalization still induce radial and transverse flows, thereby contributing to an increase in T. The effective parameters (kappa and T) are obtained by fitting the experimental pT spectra of J/psi and Y(nS) (n = 1, 2, and 3) within various rapidity intervals, produced in p + p collisions at center-of-mass energies of s=13 and 8 TeV, as measured by the LHCb Collaboration. It is found that the multi-component distribution structured within the framework of the Schwinger mechanism or Bose-Einstein statistics can effectively describe the heavy quarkonium pT spectra in small collision systems. With decreasing rapidity in the forward region, both kappa and T increase, indicating a directly proportional relationship between them. Based on kappa, the average minimum strong force radius of participant quarks is determined.
Searches are being carried out at the Large Hadron Collider (LHC) for the decay of the CP-odd scalar (A^0) in Two-Higgs-Doublet Models (2HDMs) with Natural Flavour Conservation (NFC) in the channel A^0→ h^0 Z, where h^0 is either the discovered 125 GeV Higgs boson or is an undiscovered CP-even scalar with a mass below 125 GeV. The latter possibility is called the "inverted hierarchy scenario" (IH) and would provide the opportunity of simultaneous discovery of two scalars. In both searches the selection cuts are optimised for the case of an on-shell Z boson. For the case of the Z boson being off-shell (denoted by Z^*, for which m_A^0 - m_h^0<m_Z) no limits are set on the relevant 2HDM parameters from this process. It is known that the decay A^0→ h^0 Z^* can have a large branching ratio (BR) in 2HDMs (especially in the Type I structure). In the context of the IH scenario and developing our previous work, we calculate the signal cross section σ(gg→ A^0)× BR(A^0→ h^0Z^(*))× BR(h^0→ bb,ττ) in the four types of 2HDMs with NFC. We also suggest some selection cuts that could provide sensitivity to A^0→ h^0 Z^* in the IH scenario.
We calculate the algebra of constraints for deparametrized general relativity with a space-time filling unstable D-brane for an arbitrary value of tachyon field T. We also propose observables that have vanishing Poisson brackets with all first-class constraints.
We study the phenomenological implications of the minimal supersymmetric standard model (MSSM) augmented by a nonabelian flavor symmetry labeled as sMSSM. Incorporating this flavor symmetry allows for a significant reduction in the original plethora of free parameters present in the MSSM, ultimately reducing them down to just seven in sMSSM. This reduction of free parameters is not achieved through ad hoc assumptions like in the constrained MSSM (CMSSM); rather, it is grounded in theoretical considerations. Our work focuses on exploring the interplay between the W boson mass ( M W ) predictions, the cold dark matter (CDM) relic abundance ( Ω CDM h 2 ), and the ( g − 2) μ anomaly. We identified correlations among the theoretical parameters arising from this interplay, which can be complemented by experimental constraints such as the Higgs boson mass, B‐physics observables, and charge and color breaking minima. Additionally, our investigations show that the ( g − 2) μ discrepancy and the Planck bounds on Ω C D M h 2 can be addressed within the sMSSM but only in a very narrow region of the parameter space.
Decays B ⟶DP ℓ + ν ℓ ( ℓ = e , μ , τ ) with the nonresonance, the charmed vector resonances, the charmed scalar resonances, and the charmed tensor resonances are explored by using the SU(3) flavor symmetry approach. Firstly, the decay amplitudes of different modes are related by the SU(3) flavor symmetry. Then, relevant experimental data are used to constrain nonperturbative coefficients in the nonresonant and various resonant B ⟶ D P ℓ + ν ℓ decays. Finally, using the constrained nonperturbative coefficients, the branching ratios of not‐yet‐measured B ⟶DP ℓ + ν ℓ decays with the nonresonant and various charmed resonant contributions are predicted. Many branching ratios are predicted for the first time. We find that B ⟶ D η ′ ℓ + ν ℓ , B s ⟶ D s η ′ ℓ + ν ℓ decays only receive the nonresonant contributions; B ⟶ D s K ℓ + ν ℓ , B s ⟶DK ℓ + ν ℓ , B ⟶ D η ℓ + ν ℓ , and B s ⟶ D s η ℓ + ν ℓ decays receive both the nonresonant and the tensor resonant contributions; B + ⟶ D − π + ℓ + ν ℓ decays receive the nonresonant, the scalar resonant, and the tensor resonant contributions; and other B ⟶ D π ℓ + ν ℓ decays receive all kinds of contributions. These results can be used to test the SU(3) flavor symmetry approach in the four‐body semileptonic B decays in future experiments at LHCb and Belle‐II.
Recent developments in quantum theory suggest a unified treatment of space and time, where spatial and temporal correlations can be regarded as equivalent. Specifically, spatial correlations between two systems at one time have been shown to correspond to temporal correlations of a single system at two times, via partial transposition. This formal equivalence implies a revised framework in which temporal correlations are also defined on a tensor product of Hilbert spaces. In this work, we extend these ideas to the AdS/CFT correspondence by proposing that the thermofield double state—traditionally understood as encoding spatial correlations between two CFTs—is equivalent to temporal correlations of a single CFT across two times. On the gravity side, this implies that temporal correlations correspond to one black hole at different times or two temporally separated black holes connected by an Einstein–Rosen bridge. We interpret this connection as a temporal wormhole and explore its properties, concluding that such wormholes are nontraversable. We further analyze the dual spacetime of these temporal wormholes in the context of BTZ black holes and demonstrate that interchanging space and time in the BTZ metric yields a spacetime analogous to static de Sitter space. This leads us to propose a novel link between the interior geometry of BTZ black holes and the dS/CFT correspondence, wherein quantum temporal correlations are dual to de Sitter spacetime. This framework may provide new insights into the nature of quantum gravity and spacetime structure.
We study the phenomenological implications of the minimal supersymmetric standard model (MSSM) augmented by a nonabelian flavor symmetry labeled as sMSSM. Incorporating this flavor symmetry allows for a significant reduction in the original plethora of free parameters present in the MSSM, ultimately reducing them down to just seven in sMSSM. This reduction of free parameters is not achieved through ad hoc assumptions like in the constrained MSSM (CMSSM); rather, it is grounded in theoretical considerations. Our work focuses on exploring the interplay between the W boson mass (MW) predictions, the cold dark matter (CDM) relic abundance (Omega CDMh2), and the (g - 2)mu anomaly. We identified correlations among the theoretical parameters arising from this interplay, which can be complemented by experimental constraints such as the Higgs boson mass, B-physics observables, and charge and color breaking minima. Additionally, our investigations show that the (g - 2)mu discrepancy and the Planck bounds on Omega CDMh2 can be addressed within the sMSSM but only in a very narrow region of the parameter space.
The inconsistent thermal parameters derived from various models in high‐energy collisions are examined. A comprehensive literature review suggests model‐independent parameters to address these inconsistencies, based on the average transverse momentum 〈 p T 〉 and root‐mean‐square transverse momentum . The relevant parameters include the initial temperature , effective temperature T = 〈 p T 〉/2, kinetic freeze‐out temperature T 0 = 〈 p T 〉/6.14, and average transverse velocity β T = 〈 p T 〉/2〈 m 〉, where 〈 m 〉 is the average mass of moving particles in the emission source’s rest frame. Alternatively, T 0 can be seen as the intercept in the linear relationship between T and m 0 , while β T represents the slope between 〈 p T 〉 and 〈 m 〉 (with m 0 being the rest mass of a specified particle). Our findings show that these four parameters increase in central collisions, within central rapidity regions, at higher energies, and in larger collision systems. As collision energy rises, excitation functions for all four parameters increase rapidly below approximately 7.7 GeV but slowly above this threshold. At energies greater than 39 GeV, fluctuations appear in these trends with only minor changes observed in their growth rates. This work also reveals a mass‐dependent multitemperature scenario related to both initial states and kinetic freeze‐out processes.
We investigate tensor condensates and chiral condensates in the (2 + 1)-flavor Nambu–Jona–Lasinio model at finite temperature and density in the presence of a strong magnetic field. The emergence of the tensor condensate is attributed to the four-fermion interaction. It is shown that a sufficiently large chemical potential is necessary for the occurrence of a phase transition toward tensor condensate. Furthermore, we investigate the correlation between tensor condensate and spin polarization, which accounts for the oscillatory behavior of the spin polarization during the transition from the chiral condensate to tensor condensate phase.
