arXiv subjects

Mohammad H. Alhakami

Publications and source records attributed to Mohammad H. Alhakami.

9 recordsLinked to original sources

arXiv2026

Coherent control of the Goos-Hänchen shift in Otto structure

We investigate controlling the lateral Goos-Hänchen (GH) shift for a TM-polarized field reflected from Otto structure containing four level N-type atomic medium. The N-type atomic configuration can be formed by coupling the standard three-level $Λ$ system to an additional upper energy level through a coherent driving field. The medium can then be switched from transparent to absorptive under the effect of the driving field. In the Otto structure, an air gap typically separates a dielectric prism from a metal film. We show that the sign and magnitude of the GH shift can be highly controlled when the air gap is replaced by the coherent atomic medium. This can be achieved by adjusting the strength of the applied fields to the atomic medium, while the geometrical characteristics of the proposed structure are unchanged.

physics.optics↗

arXiv2022

Hadronic loop effects to excited scalar charmed mesons revisited

We re-examine the hadronic loop effects to the masses of $D^*_0$ and $D^*_{s0}$ calculated in quark models in the framework of heavy meson chiral perturbation theory (HMCHPT). The inaccuracy in the choice of the argument of the chiral loop functions in previous works is corrected. Our calculations consider the full one-loop corrections that appear at leading order in the chiral expansion of the effective Lagrangian. Unlike previous approaches, ours leads to satisfactory results in explaining the low mass of the observed scalar charm states reported by the Particle Data Group (PDG). It is found that the mass shift of bare $D^*_{s0}$ ($D^*_{0}$) state is mainly due to the $DK$ ($Dπ$) loop corrections for values of the couplings that are compatible with the measured ones. We show why previous approaches of using HMCHPT in studying mass shift effects due to chiral loops gave unsatisfactory results.

hep-ph↗

arXiv2021

Predictions for the beauty meson spectrum

We predict the spectrum of the four $1S$ and eight $1P$ nonstrange and strange states in the beauty meson family in the context of effective field theory. By the union of heavy quark effective theory and chiral perturbation theory, the mass formalisms for the heavy-light mesons are defined. Our analysis uses mass expressions involving, for the first time, the full leading self-energy corrections and leading power corrections to the heavy quark and chiral limits. The counterterms present in these expressions are fitted using available experimental and theoretical information on the charmed meson masses and couplings. The results from charm sector are used to make theoretical expectations on the analog beauty meson spectrum. The observed spectrum of the ground state, $B^{(*)}_{(s)}$, and excited, $B_{(s)1}$ and $B^*_{(s)2}$, beauty mesons are well reproduced in our theoretical calculations. The excited scalar, $B^*_{(s)0}$, and axial-vector, $B^\prime_{(s)1}$, beauty mesons have not yet been discovered. Hopefully our predictions may provide valuable clues to further experimental exploration of these missing resonances.

hep-ph↗

arXiv2020

Spectroscopy of excited charmed mesons

We derive mass formulas for the $P$-wave orbitally excited $D^*_{0(s)}$, $D^\prime_{1(s)}$, $D_{1(s)}$, and $D^*_{2(s)}$ heavy charmed mesons including all effects from one-loop corrections that contribute at leading order in chiral expansion. In our formalism, the effects to first order in $m_q$, where $m_q$ is the light quark mass, and to first order in $m^{-1}_c$, where $m_c$ is the charm quark mass, and $m_q/m_c$ terms are considered. The experimental and lattice QCD results on the charmed meson spectra are employed to fix the large number of counterterms appearing in the effective chiral Lagrangian used in this work. This allows us to test the validity of perturbative expansion of our theory. The results presented in the current paper are useful to other applications of excited charmed and bottom meson systems.

hep-ph↗

arXiv2018

Low-energy constants of heavy meson effective theory in lattice QCD

We consider effective theory treatment for the lowest-lying $S$- and $P$-wave states of charmed mesons. In our analysis, quantum corrections and contributions from leading chiral and heavy quark symmetry breakings are taken into account. The heavy meson mass expressions have abundance parameters, low-energy constants, in comparison to the measured charmed mesons masses. The experimental and lattice QCD data on charmed meson spectroscopy are used to extract, for the first time, the numerical values of the full set of low-energy constants of the effective chiral Lagrangian. Our results on these parameters can be used for applications on other properties of heavy-light meson systems.

hep-ph↗

arXiv2017

Short-range interactions and narrow resonances in effective field theory

We consider the effective field theory (EFT) treatment of two-body systems with narrow resonances. Within this approach, an $s$-wave scattering amplitude can be expanded in powers of a typical momentum scale of a system $Q\ll Λ$, where $Λ$ represents a hard scale of a scattering system and an energy difference $δε=|E-ε_0|\ll ε_0$, where $ε_0$ is a resonance peak energy. It is shown that at leading order in the double expansion a universal form of a two-body scattering amplitude is a sum of a Breit-Wigner term of order $Q^{-1}$, a smooth background term of order $Q^0$, and an interference term of order $Q^0$. The techniques developed in this paper can be used to investigate the properties of narrow resonances that are produced by short-distance dynamics.

nucl-th↗

arXiv2016

Odd- and even-parity charmed mesons revisited in heavy hadron chiral perturbation theory

We study the masses of the low-lying charmed mesons within the framework of heavy-hadron chiral perturbation theory. We work to third order in the chiral expansion, where meson loops contribute. In contrast to previous approaches, we use physical meson masses in evaluating these loops. This ensures that their imaginary parts are consistent with the observed widths of the D-mesons. The lowest odd- and even-parity, strange and nonstrange mesons provide enough constraints to determine only certain linear combinations of the low-energy constants in the effective Lagrangian. We comment on how lattice QCD could provide further information to disentangle these constants.

hep-ph↗

arXiv2016

Mass Spectra of Heavy-Light Mesons in Heavy Hadron Chiral Perturbation Theory

We study the masses of the low-lying charm and bottom mesons within the framework of heavy- hadron chiral perturbation theory (HHChPT). We work to third order in the chiral expansion, where meson loops contribute. In contrast to previous approaches, we use physical meson masses in evaluating these loops. This ensures that their imaginary parts are consistent with the observed widths of the D-mesons. The lowest odd- and even-parity, strange and nonstrange charm mesons provide enough constraints to determine only certain linear combinations of the low-energy constants (LECs) in the effective Lagrangian. We comment on how lattice QCD could provide further information to disentangle these constants. Then we use the results from the charm sector to predict the spectrum of odd- and even-parity of the bottom mesons. The predicted masses from our theory are in good agreement with experimentally measured masses for the case of the odd-parity sector. For the even-parity sector, the B-meson states have not yet been observed; thus, our results provide useful information for experimentalists investigating such states. The near degeneracy of nonstrange and strange scalar B mesons is confirmed in our predictions using HHChPT. We show why previous approaches of using HHChPT in studying the mass degeneracy in the scalar states of charm and bottom meson sectors gave unsatisfactory results.

hep-ph↗

arXiv2015

Power counting for three-body decays of a near-threshold state

We propose a new power counting for the effective field theory describing a near-threshold state with unstable constituents, such as the X(3872) meson. In this counting, the momenta of the heavy particles, the pion mass and the excitation energy of the unstable constituent -- the D* in the case of the X -- are treated as small scales, of order Q. The difference, delta, between the excitation energy of the D* and the pion mass is smaller than either by a factor ~20. We therefore assign delta an order Q^2 in our counting. This provides a consistent framework for a double expansion in both delta/m_pi and the ratio of m_pi to the high-energy scales in this system. It ensures that amplitudes have the correct behaviour at the three-body threshold. It allows us to derive, within an effective theory, various results which have previously been obtained using physically-motivated approximations.

hep-ph↗