arXiv subjects

Y. Sarac

Publications and source records attributed to Y. Sarac.

At least 19 recordsLinked to original sources

arXiv2026

Interpreting the Newly Observed $\Xi(1720)$ State in the Spin-$\frac{3}{2}$ $\Xi$ Spectrum

We analyze the low lying spin-$\frac{3}{2}$ $\Xi$ spectrum by means of the two point QCD sum rule approach. The analysis is motivated by the BESIII observation of the $\Xi(1720)$ resonance, reported with mass $1721.0\pm5.2_{\mathrm{stat.}}\pm3.4_{\mathrm{syst.}}~\mathrm{MeV}$ and favored quantum numbers $J^P=\frac{3}{2}^{+}$. In this framework, we include the $1S$, $1P$, $2S$ and $2P$ configurations as possible low lying spin-$\frac{3}{2}$ cascade states. The extracted masses are $1527.53\pm111.38~\mathrm{MeV}$, $1615.30\pm50.98~\mathrm{MeV}$, $1727.52\pm42.39~\mathrm{MeV}$ and $1803.71\pm64.50~\mathrm{MeV}$ for the $1S$, $1P$, $2S$ and $2P$ states, respectively. The mass obtained for the $2S$ configuration agrees with the BESIII value within uncertainties and favors the assignment of $\Xi(1720)$ as the first radial spin-$\frac{3}{2}$ excitation of the $\Xi$ baryon.

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arXiv2026

Analysis of Fully Heavy $P_{(3c2b)}$ and $P_{(3b2c)}$ Pentaquark Candidates

Recent progress in experimental facilities, together with larger data samples and more refined analysis strategies has enabled the observation of many exotic hadronic states, adding new members to the hadron spectrum. Each newly reported signal encourages further experimental searches and simultaneously motivates theoretical studies aimed at uncovering additional nonconventional states. Motivated by this perspective and by the increasing interest in systems containing multiple heavy quarks, we present a spectroscopic study of fully heavy pentaquark candidates with spin-parity quantum numbers $J^{P}=\frac{1}{2}^{-}$ and quark contents $QQQ'Q\bar{Q'}$, $QQQ'Q'\bar{Q}$, and $Q'Q'QQ\bar{Q}$, where $Q(Q')$ represents either $c(b)$ or $b(c)$ quarks. We employ the QCD sum rule approach with three different types of interpolating currents to obtain the corresponding masses and current coupling constants of the considered states. The following masses for the states containing three $c$ and two $b$ quarks are predicted: $m_{(3c2b)}=14479.30\pm75.06~\mathrm{MeV}$ using the current $J_1$, $\tilde{m}_{(3c2b)}=14276.80\pm76.29~\mathrm{MeV}$ using $J_2$, and $\bar{m}_{(3c2b)}=14276.80\pm76.29~\mathrm{MeV}$ using $J_3$. The corresponding predictions for the states containing three $b$ and two $c$ quarks are as $m_{(3b2c)}=17458.90\pm130.11~\mathrm{MeV}$ with $J_1$, $\tilde{m}_{(3b2c)}=17202.70\pm132.37~\mathrm{MeV}$ with $J_2$, and $\bar{m}_{(3b2c)}=17250.80\pm131.98~\mathrm{MeV}$ with $J_3$, respectively. In addition, we provide the corresponding current coupling constants, which can serve as useful inputs for analyses of decay properties and interaction mechanisms of these fully heavy pentaquark candidates.

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arXiv2026

Light cone QCD sum rules study of the rare radiative $\Xi^{*}_{bb}\to\Xi_b\gamma$ decay

The rare radiative decay $\Xi^{*}_{bb}\to\Xi_b\gamma$ is investigated within the light cone QCD sum rules approach. This decay proceeds through the flavor changing neutral current $b\to s$ transition in the Standard Model. The hadronic matrix element of the considered decay is parameterized in terms of four tensor form factors $T_1^{V}(q^2)$, $T_2^{V}(q^2)$, $T_1^{A}(q^2)$ and $T_2^{A}(q^2)$. The sum rules for these form factors describing the $\Xi^{*}_{bb}\to\Xi_b\gamma$ decay are derived at $q^2=0$ point using the $\Xi_b$ distribution amplitudes. The results of the form factors are employed to calculate the corresponding decay width. Our finding indicates that this weak radiative decay could be within reach of future high statistics studies of doubly heavy baryons at LHCb and upcoming facilities.

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arXiv2025

Analysis of the $B_{(s)}\rightarrow T(J^P=2^-)$ transition in light cone QCD sum rules

The semileptonic $B_{(s)} \rightarrow T(J^P=2^-)l^+l^-$ decays induced by flavor changing neural currents are investigated within the light cone QCD sum rule method. We apply the $B$ meson distribution amplitudes up to twist-4 and calculate the relevant form factors of the $B_{(s)} \rightarrow T$ transitions, where $T=K_2,~a_2,~f_2,~ϕ_2$ with $J^P=2^-$. The obtained results of the form factors then adopted in the calculations of the corresponding widths. The present results can be used in future experiments for studying the properties of $J^P=2^-$ tensor mesons.

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arXiv2025

Investigation of full heavy $ QQQQ'\bar{Q}$ pentaquark candidates

Recent breakthroughs in research and experimentation have led to the identification of numerous exotic states in particle physics. Each new discovery not only sparks excitement for future findings but also fuels interest in uncovering additional unknown states. Motivated by this perspective and the recent identification of both standard and exotic hadrons with an increasing number of heavy quarks, this study conducts a spectroscopic analysis of possible pentaquark candidates with spin-parity $\frac{1}{2}^-$, and quark content of $cccb\bar{c}$ and $bbbc\bar{b}$. The masses of these states are calculated by considering the relevant Lorentz structures, including $\slashed{p}$ and $\mathbbm{1}$, yielding the following results, respectively: for the $P_{(4cb)}$ state, $m_{P_{(4cb)}} = 11388.30 \pm 107.79$~MeV and $m_{P_{(4cb)}} = 11368.30 \pm 112.68$~MeV, and for the $P_{(4bc)}$ state, $m_{P_{(4bc)}} = 20998.30 \pm 121.52$~MeV and $m_{P_{(4bc)}} = 20990.50 \pm 125.87$~MeV. Additionally, the current coupling constants of these states to the vacuum, which are essential for analyzing their potential decay modes, are also provided in this study.

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arXiv2024

Investigation of full-charm and full-bottom pentaquark states

The continuous advancement of experimental techniques and investigations has led to observations of various exotic states in particle physics. Each addition to this family of states not only raises expectations for future discoveries but also focuses attention on such potential new states. Building upon this motivation and inspired by recent observations of various traditional and exotic particles containing an increased number of heavy quarks, our study provides a spectroscopic search for potential pentaquark states with spin-parity $\frac{3}{2}^-$ and composed entirely of charm or bottom quarks. We predict the masses for full-charm and full-bottom pentaquark states as $m = 7628 \pm 112$~MeV and $m = 21982 \pm 144$~MeV, respectively. We also compute the current couplings of these states to vacuum, which are main inputs in investigations of their various possible decays.

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arXiv2024

Investigations of $Λ$ states with spin-parity $\frac{3}{2}^{\pm}$

The present study provides spectroscopic investigations of spin-$\frac{3}{2}$ $Λ$ baryons with both positive and negative parities. The analysis mainly focuses on three states, namely $1P$, $2P$, and $2S$, and corresponding masses are calculated using the QCD sum rule method. To implement the method, we apply two types of interpolating currents with octet and singlet quantum numbers and compare the corresponding results with the reported masses of experimentally observed states. From the comparisons, it is extracted that the results of interpolating current with octet quantum numbers are in good agreement with the experimentally measured masses. The masses obtained with this interpolating current are $m=1513.64\pm 8.76$ MeV for $1P$ state with $J^P=\frac{3}{2}^-$, $m'=1687.91\pm 0.31$ MeV for $2P$ state with $J^P=\frac{3}{2}^-$ and $\tilde{m}=1882.37 \pm 11.95$ MeV for $2S$ state with $J^P=\frac{3}{2}^+$ and they are consistent with the experimental masses of $Λ(1520)$, $Λ(1690)$ and $Λ(1890)$, respectively, which confirm their spin-parity quantum numbers. Besides, we calculate the corresponding current coupling constants, which are utilized as inputs in the calculations of different form factors defining the widths of the states under study.

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arXiv2023

Re-analysis of rare radiative $Ξ_b^-\rightarrow Ξ^- γ$ decay in QCD

The upper limit of the branching ratio of the rare $Ξ_b^-\rightarrow Ξ^- γ$ decay is obtained as $BR(Ξ_b^-\rightarrow Ξ^- γ)<1.3\times10^{-4}$ by the LHCb. In the present work we study this decay within the light cone QCD sum rules employing the $Ξ_b$ distribution amplitudes. At first stage, the form factors entering the $Ξ_b^-\rightarrow Ξ^- γ$ decay are obtained. Next, using the results for the form factors the corresponding branching ratio for this decay is estimated to be $BR(Ξ_b^-\rightarrow Ξ^- γ)=(4.8\pm 1.3)\times 10^{-5}$. This value lies below the upper limit established by the LHCb collaboration. Our finding for the branching ratio is also compared with the results of the other theoretical approaches existing in the literature.

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arXiv2023

Investigation of $Λ(1405)$ as a molecular pentaquark state

$Λ(1405)$ is one of the interesting particles with its unclear structure and distinct properties. It has a light mass compared to its non-strange counterpart, despite the strange quark it carries. This situation puts the investigation of this resonance among the hot topics in hadron physics and collects attention to clarify its properties. In this study, we focus on the calculation of the mass and residue of the $Λ(1405)$ resonance within the framework of QCD sum rules. We assign a structure in the form of a molecular pentaquark composed from admixture of $K^-$ meson-proton and $\bar{K}^0$ meson-neutron. Using an interpolating current in this form, the masses and the current coupling constant are attained as $m=1406\pm 128~\mathrm{MeV}$ and $λ=(3.35\pm 0.35)\times10^{-5}~\mathrm{GeV}^6$ for $\slashed{q}$ and $m=1402\pm 141~\mathrm{MeV}$ and $λ=(4.08\pm 1.08)\times10^{-5}~\mathrm{GeV}^6$ for $I$ Lorentz structures entering the calculations, respectively. The obtained mass values agree well with the experimental data supporting the plausibility of the considered structure.

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arXiv2023

Investigation of the strange pentaquark candidate $P_{ψs}^Λ(4338){}^0$ recently observed by LHCb

The recently observed strange pentaquark candidate, $P_{ψs}^Λ(4338){}^0$, is investigated to provide information about its nature and substructure. To this end, its mass and width through the decay channels $P_{ψs}^Λ(4338){}^0 \rightarrow J/ψΛ$ and $P_{ψs}^Λ(4338){}^0 \rightarrow η_c Λ$ are calculated by applying two- and three-point QCD sum rules, respectively. The state is considered as a $Ξ_c\bar{D}$ meson-baryon molecular structure with spin-parity quantum numbers $J^P=\frac{1}{2}^-$. The obtained mass, $m_{P_{ψs}^Λ(4338){}^0}=4338\pm 130~\mathrm{MeV}$, and width, $Γ_{P_{ψs}^Λ(4338){}^0}= 10.40\pm 1.93~\mathrm{MeV}$, are consistent with the experimental data within the presented uncertainties. This allows us to assign a $Ξ_c\bar{D}$ molecular structure of $J^P=\frac{1}{2}^-$ for the $P_{ψs}^Λ(4338){}^0$ state.

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arXiv2023

Investigation of a candidate spin-$\frac{1}{2}$ hidden-charm triple strange pentaquark state $P_{csss}$

A candidate triple strange pentaquark state, $P_{csss}$, is investigated through its strong decay channel $P_{csss} \rightarrow Ω^-J/ψ$. To calculate the relevant strong coupling constants, two possible interpolating currents with spin-parity $J^P=\frac{1}{2}^{-}$ are used. Though the chosen currents for the state under consideration have spin-parity quantum numbers $J^P=\frac{1}{2}^{-}$, they couple to both the positive and negative parity states simultaneously and the corresponding decay widths are obtained for both parities. These widths are obtained as $Γ(P_{csss} \rightarrow J/ψΩ^-)=201.4\pm 82.5~\mathrm{MeV}$ for the negative and $Γ(\widetilde{P}_{csss} \rightarrow J/ψΩ^-)=316.4\pm 107.8~\mathrm{MeV}$ for the positive parity state when the first current is used. For the second current, we obtain $Γ(P_{csss} \rightarrow J/ψΩ^-)=252.5\pm 116.7~\mathrm{MeV}$ for the negative and $Γ(\widetilde{P}_{csss} \rightarrow J/ψΩ^-)=361.1\pm 98.4~\mathrm{MeV}$ for the positive parity state. These results may provide insights into future experimental observations of such candidate states and help to distinguish and fix their properties.

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arXiv2022

Interpretation of the $Λ_c(2910)^+$ baryon newly seen by Belle Collaboration and its possible bottom partner

The developments in the experimental facilities and analyses techniques have recently lead to the observation of many hadronic states ranging from excitations of conventional hadrons to various exotic states. The baryons with single heavy quark are among these states providing an attractive field of research to get a better understanding of the nonperturbative nature of the strong interaction. Recently, the Belle Collaboration announced observation of the state $Λ_c(2910)^+$ with a mass $2913.8\pm5.6\pm3.8~\mathrm{MeV}/c^2$ and width $51.8\pm20.0\pm18.8~\mathrm{MeV}$. In the present study, by the mass analyses of different excitations at $Λ_c$ channel and their comparison with existing experimental information, we find that the spin-parity of this newly found excited state is $ J^P= \frac{1}{2}^-$ and it is a $ 2P $ state denoting by $Λ_c(\frac{1}{2}^-,2P)$. We predict its current coupling as well, which can be served as one of the main input parameters to investigate different decays and interactions of this particle. We also determine the mass and current coupling of $Λ_b(\frac{1}{2}^-,2P)$ as possible bottom counterpart of the new $Λ_c(2910)^+$ state, which may be in agenda of different experiments in near future.

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arXiv2022

Investigation of hidden-charm double strange pentaquark candidate $P_{css}$ via its mass and strong decays

This work presents an analysis of a hidden charmed pentaquark candidate state with double strange quark in its quark content. The investigation is performed in two parts, which provide the mass prediction of the considered state and its partial decay widths for the $P_{css}\rightarrow Ξ^0 J/ψ$ and $P_{css}\rightarrow Ξ_c^+ D_s^-$ channels. For the analyses, two-point and three-point QCD sum rule methods are applied to get the mass and the widths, respectively. The mass for this candidate state is obtained as $m_{P_{css}}=4600 \pm 155$ MeV with corresponding current coupling constant $λ_{P_{css}}=(0.81 \pm 0.21)\times 10^{-3}$ GeV$^6$. These results are used in the analysis of the partial widths of this state for the decays $P_{css}\rightarrow Ξ^0 J/ψ$ and $P_{css}\rightarrow Ξ_c^+ D_s^-$. From these decays, the total width is obtained as $Γ= 12.29\pm 2.94 $ MeV. These results may shed light on the future experimental searches in which such types of states are probed and may provide information to discriminate between such possible observations.

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arXiv2021

Investigation of $P_{cs}(4459)^0$ pentaquark via its strong decay to $ΛJ/Ψ$

Recently the observation of a new pentaquark state, the hidden-charmed strange $P_{cs}(4459)^0$, was reported by the LHCb Collaboration. The spin-parity quantum numbers of this state were not determined as a result of insufficient statistics. To shed light on its quantum numbers, we investigate its decay, $P_{cs}(4459)^0 \rightarrow J/ψΛ$, the mode that this state has been observed, within the QCD sum rule framework. We obtain the width of this decay assigning the spin-parity quantum numbers of $P_{cs}(4459)^0$ state as $J^P=\frac{1}{2}^-$ and its substructure as diquark-diquark-antiquark. To this end, we first calculate the strong coupling constants defining the considered decay and then use them in the width calculations. The obtained width is consistent with the experimental observation, confirming the quantum numbers $J^P=\frac{1}{2}^-$ and compact pentaquark nature for $P_{cs}(4459)^0$ state.

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arXiv2021

Properties of $P_c(4312)$ pentaquark and its bottom partner

We present an analysis of the newly observed pentaquark $P_c(4312)^+$ to shed light on its quantum numbers. To do that, the QCD sum rule approach is used. The measured mass of this particle is close to $Σ_c^{++}\bar{D}^-$ threshold and has a small width, which supports the possibility of its being a molecular state. We consider an interpolating current in a molecular form and analyze both the positive and negative parity states with spin-$\frac{1}{2}$. We also consider the bottom counterpart of the state with similar molecular form. Our mass result for the charm pentaquark state supports that, the quantum numbers of the observed state are consistent with $J^P=\frac{1}{2}^{-}$.

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arXiv2021

Determination of the possible quantum numbers for the newly observed $Ξ_b(6227)^0$ state

The LHCb Collaboration recently reported the observation of a new excited bottom baryon $Ξ_b(6227)^0$ and announced an improvement in the measurements related to the previously observed $Ξ_b(6227)^-$ state. We conduct an analysis for $Ξ_b(6227)^0$ state considering it as isospin partner of the $Ξ_b(6227)^-$ resonance and possibly $1P$ or $2S$ excited state with spin $J=\frac{3}{2}$. The corresponding masses for both possibilities have consistent results with the experimental data, indicating that only with the mass sum rules, one can not make exact decision on the nature and quantum numbers of this state. To go further, the decays of these possible excited states to $Ξ_b^- π^+$ final state are also considered and the relevant strong coupling constants are extracted from the light cone sum rules. The obtained decay width values support the possibility of $Ξ_b(6227)^0$ to be the $1P$ excited state of $Ξ_b(5945)^0$ baryon.

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arXiv2020

New $Λ_b(6072)^0$ state as a $2S$ bottom baryon

As a result of continuous developments, the recent experimental searches lead to the observations of new particles at different hadronic channels. Among these hadrons are the excited states of the heavy baryons containing single bottom or charmed quark in their valance quark content. The recently observed $Λ_b(6072)^0$ state is one of these baryons and possibly $2S$ radial excitation of the $Λ_b$ state. Considering this information from the experiment, we conduct a QCD sum rule analysis on this state and calculate its mass and current coupling constant considering it as a $2S$ radially excited $Λ_b$ resonance. For completeness, in the analyses, we also compute the mass and current coupling constant for the ground state $Λ_b^0$ and its first orbital excitation. We also consider the $Λ_c^+$ counterpart of each state and attain their mass, as well. The obtained results are consistent with the experimental data as well as existing theoretical predictions.

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arXiv2020

Nucleon resonances with spin $\frac{3}{2}$ and isospin $\frac{1}{2}$

Investigation of the nucleon's excited states has always become an important research topic because of the rich information they provide. Since their first observation, dating back about 70 years, the investigation of their various parameters contributed both to the development of the quark model and better understanding of the QCD as the theory of strong interaction. Their investigation still has importance. The researches conducted on the nucleon excited states are helpful to probe missing resonances predicted by the quark model but not observed yet. With this motivation, we study the low lying nucleon resonance with $I(J^P)=\frac{1}{2}(\frac{3}{2}^{-})$ and its corresponding orbital and radial excitations with $I(J^P)=\frac{1}{2}(\frac{3}{2}^+)$ and $I(J^P)=\frac{1}{2}(\frac{3}{2}^-)$, respectively. Using the QCD sum rule method, we calculate the masses and pole residues of these states. The obtained mass results are consistent with the mass ranges presented in PDG for the resonances $N^*(1520)(3/2^-)$, $N^*(1700)(3/2^-)$, and $N^*(1720)(3/2^+)$. The results of masses and residues of these states may be used as input parameters to calculate various quantities related to their electromagnetic, weak and strong interactions with other particles with the aim of getting more information on their nature and structure.

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