arXiv subjects

E. K. Karkaryan

Publications and source records attributed to E. K. Karkaryan.

11 recordsLinked to original sources

arXiv2026

Sgoldstino Phenomenology at SND@HL-LHC

We study the phenomenology of light scalar sgoldstinos, with masses from the dimuon threshold up to a few GeV, focusing on their production and detection prospects at the SND@HL-LHC experiment. We review the effective sgoldstino interactions with Standard Model particles, the dominant meson-decay production channels, and the relevant experimental constraints on the model parameter space. We also outline the recently proposed SND@HL-LHC detector configuration and discuss the kinematics and track separation of the muon pair produced in sgoldstino decays inside the detector volume. For two representative sets of supersymmetry-breaking parameters, we present sensitivity estimates and show that the muon-antimuon separation efficiency should be taken into account in searches for the dimuon signal.

hep-ph↗

arXiv2025

Does the existence of $f_0$ meson enlarge the $K^+ \to π^0π^0π^0 e^+ ν$ decay probability?

We estimate a possible contribution of the two-pion system $f_0(500)$ wide resonance to the decay probability of the super rare decay $K^+ \to 3π^0 e^+ ν$. We vary the width of the resonance from 0.01 MeV to 1000 MeV. We found that the contribution of the narrow resonance in a system of several final state particles into the decay probability is proportional to its width. However it never exceeds the value of the decay probability calculated on free final state particles neglecting the resonance contribution.

hep-ph↗

arXiv2025

On the determination of the relative probability of $\mathitΥ(5S) \rightarrow B_s^{()}\bar B^{()}_s$ decays

Semileptonic decays of the $B \overline{B}$ pairs produced in the $\mathitΥ(5S)$ can be used to find the relative probability of $\mathitΥ(5S) \rightarrow B_s \overline{B}_s$ decays. This could be achieved by the study of time dependence of $B$-meson decays to the leptons of equal and opposite signs.

hep-ph↗

arXiv2025

On the $K^+ \to π^0π^0π^0 e^+ ν$ decay

The OKA Collaboration has obtained a new upper limit on the $K^+ \to π^0π^0π^0 e^+ ν$ decay probability which is 65 times lower than the one currently listed by PDG. However it is still about $10^{4}$ times worse than the theoretical prediction. It was suggested that production of pionium $A_{2π}$ in the final state of the semileptonic $K^+$ decay with subsequent $A_{2π} \to π^0 π^0$ decay will increase the value of theoretical branching ratio due to the absence of five-particle phase space suppression. The estimates done in our paper show that despite the gain in the phase space the decay $K^+ \to A_{2π}π^0 e^+ ν$ appeares to be strongly suppressed because of the smallness of the pionium wave function at zero $π$ mesons separation.

hep-ph↗

arXiv2024

libepa -- a C++/Python library for calculations of cross sections of ultraperipheral collisions

The library provides a set of C++/Python functions for computing cross sections of ultraperipheral collisions of high energy particles under the equivalent photons approximation. Cross sections are represented through multiple integrals over the phase space. The integrals are calculated through recurrent application of algorithms for one dimensional integration. The paper contains an introduction to the theory of ultraperipheral collisions, discusses the library approach and provides a few examples of calculations.

hep-ph↗

arXiv2023

On production of heavy charged particles in $γγ$ fusion at planned $pp$ colliders

Production of heavy fermions in ultraperipheral collisions ($pp\to p+γγ+p\to p+χ^{+}χ^{-}+p$) and the semiexclusive reaction ($pp \to p+γγ^{*}+X \to p+χ^{+}χ^{-}+X$) is considered. Differential and total cross sections for the energies of the planned $pp$ colliders are presented.

hep-ph↗

arXiv2023

Weak interaction corrections to muon pair production via the photon fusion at the LHC

Analytical formulas describing the correction due to the $Z$ boson exchange to the cross section of the reaction $pp\rightarrow pμ^+μ^- X$ are presented. When the invariant mass of the produced muon pair $W\gtrsim 150~\text{GeV}$ and its total transverse momentum is large, the correction is of the order of 20%.

hep-ph↗

arXiv2023

$pp$ scattering at the LHC with the lepton pair production and one proton tagging

Analytical formulas for the cross section of the reaction $pp \to p + \ell^+ \ell^- + X$ are presented. Fiducial cross sections are compared with those measured recently by the ATLAS collaboration.

hep-ph↗

arXiv2021

CP-violation in oscillations of three neutrino generations: the case of degenerate masses

CP-symmetry violates in oscillations of neutrinos in vacuum in presence of three generations. In this case there is an inherent complex phase in PMNS-matrix. When any two neutrino masses degenerate the CP-violation vanishes. In the present article different mechanisms of CP-symmetry recovery are demonstrated in case of two degenerate neutrino mass-states.

hep-ph↗

arXiv2021

Forward proton scattering in association with muon pair production via the photon fusion mechanism at the LHC

Dilepton production in proton-proton collision through $γγ$-fusion with one proton scattered elastically while the second produces a hadron jet is considered. Semi-analytical formulas describing the cross section of a muon pair production are presented.

hep-ph↗

arXiv2021

LHC as a photon-photon collider: bounds on $Γ_{X\toγγ}$

In the relatively recent CMS data, there is a hint on the existence of a resonance with the mass 28 GeV coupling to muons. Such a resonance should also couple to photons through the fermion loop, therefore it can be searched for in ultraperipheral collisions (UPC) of protons. We set an upper bound on the $X γγ$ coupling constant from the data on $μ^+ μ^-$ pair production in UPC at the LHC. Our approach can be used for similar resonances should they appear in the future.

hep-ph↗