17 results
Search Results
Now showing 1 - 10 of 17
Article Citation - WoS: 31Citation - Scopus: 30Structure of the Ξb< Resonance(Amer Physical Soc, 2018) Aliev, T. M.; Azizi, K.; Sarac, Y.; Sundu, H.We explore the recently observed Xi(b)(6227)(-) resonance to fix its quantum numbers. To this end, we consider various possible scenarios: It can be considered as either a 1P or 2S excitation of the Xi(b) and Xi'(b)(5935) ground-state baryons with spin-1/2 or the 1P or 2S excitation of the ground-state Xi(b)(5955) with spin-3/2. We calculate the masses of the possible angular-orbital 1P and 2S excited states corresponding to each channel employing the QCD sum rule technique. It is seen that all the obtained masses are in agreement with the experimentally observed value, implying that the mass calculations are not enough to determine the quantum numbers of the state under question. Therefore, we extend the analysis to investigate the possible decays of the excited states into Lambda K-b(0)- and Xi(-)(b) pi. Using the light cone QCD sum rule method, we calculate the corresponding strong coupling constants, which are used to extract the decay widths of the modes under consideration. Our results on decay widths indicate that the Xi(b)(6227)(-) is a 1P angular-orbital excited state of the Xi(b)(5955) baryon with quantum numbers J(P) = 3/2(-).Article Citation - WoS: 28Citation - Scopus: 27Lepton Flavor Universality Violation in Semileptonic Tree Level Weak Transitions(Amer Physical Soc, 2019) Azizi, K.; Sarac, Y.; Sundu, H.The recent deviations of the experimental data on some parameters of the tree-level semileptonic B and B-c mesons decays from the standard model (SM) predictions indicate considerable violations of the lepton flavor universality, and as a result possible new physics (NP) effects. To better understand the possible NP effects it is necessary to study deeply the physical quantities defining these decays from many aspects. The calculations of the physical quantities require the determinations of the hadronic form factors entering the matrix elements of the considered transitions as the main inputs. We calculate the form factors governing the tree-level B-c -> J/psi l nu and B-c -> eta(c)l nu transitions within the QCD sum rules method. The obtained form factors are used in the calculations of the branching ratios (BRs) of the B-c -> J/psi l nu and B-c -> eta(c)l nu transitions as well as R(J/psi) and R(eta(c)). Our result on R(J/psi) supports the present tension between the SM theory prediction and the experimental data. Our result on R(eta(c)) can be checked in future experiments.Article Citation - WoS: 19Citation - Scopus: 17Strong ΛbNB and ΛcND vertices(Amer Physical Soc, 2014) Azizi, K.; Sarac, Y.; Sundu, H.We investigate the strong vertices among the Lambda(b), nucleon, and B meson as well as the Lambda(c), nucleon, and D meson in QCD. In particular, we calculate the strong coupling constants g Lambda bNB and g Lambda cND for different Dirac structures entering the calculations. In the case of the Lambda cND vertex, we compare the result with the only existing prediction obtained at Q(2) = 0.Article Citation - WoS: 12Citation - Scopus: 12New Λb< State as a 2s Bottom Baryon(Amer Physical Soc, 2020) Azizi, K.; Sarac, Y.; Sundu, H.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 Lambda(b)(6072)(0) state is one of these baryons and possibly 2S radial excitation of the Lambda(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 Lambda(b) resonance. For completeness, in the analyses, we also compute the mass and current coupling constant for the ground state Lambda(0)(b) and its first orbital excitation. We also consider the Lambda(+)(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.Article Citation - Scopus: 1Investigations of Λ States With Spin-Parity 3 ± 2(Amer Physical Soc, 2024) Azizi, K.; Sarac, Y.; Sundu, H.The present study provides spectroscopic investigations of spin-32 A 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 +/- 8.76 MeV for 1P state with JP = 3 -, m' = 1687.91 +/- 0.31 MeV for 2P state with JP = 3 - and m = 1882.37 +/- 11.95 MeV for 2S state with JP = 3 + and they are consistent with the experimental masses of A(1520), A(1690), and A(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.Article Citation - WoS: 17Citation - Scopus: 18Λb< State Newly Observed by Lhcb(Amer Physical Soc, 2020) Azizi, K.; Sarac, Y.; Sundu, H.We study the bottom Lambda(b)(6146)(0) baryon, newly discovered by the LHCb Collaboration. By adopting an interpolating current of (L-rho, L-lambda) = (0, 2) type and D-wave nature with spin-parity quantum numbers J(P) = 3/2(+) for this heavy bottom baryon, we calculate its mass and residue. Using these spectroscopic parameters, we also investigate its dominant decays Lambda(b)(6146)(0) -> Sigma(b)pi and Lambda(b)(6146)(0) -> Sigma(*)(b)pi and estimate the width of Lambda(b)(6146)(0) obtained via these channels. The obtained mass, m(Lambda b) = (6144 +/- 68) MeV is in accord nicely with the experimental data. The width obtained via the dominant channels is also consistent with the experimental data of LHCb collaboration. We calculate the spectroscopic parameters and the same decay channels for the c-partner of Lambda(b)(6146)(0) state, namely Lambda(c)(2860)(+), as well. We compare the obtained results with the existing theoretical predictions as well as experimental data. The results indicate that the state Lambda(b)(6146)(0) and its charmed-partner Lambda(c)(2860)(+) can be considered as 1D-wave baryons with J(P) = 3/2(+).Article Citation - WoS: 28Citation - Scopus: 28Hidden Bottom Pentaquark States With Spin 3/2 and 5/2(Amer Physical Soc, 2017) Azizi, K.; Sarac, Y.; Sundu, H.Theoretical investigations of the pentaquark states that were recently discovered provide important information on their nature and structure. It is necessary to study the spectroscopic parameters, like masses and residues of particles belong to the class of pentaquarks, and ones having similar structures. The mass and pole residue are quantities that emerge as the main input parameters in exploration of the electromagnetic strong and weak interactions of the pentaquarks with other hadrons in many frameworks. This work deals with a QCD sum rule analysis of the spin-3/2 and spin-5/2 bottom pentaquarks with both positive and negative parities aiming to evaluate their masses and residues. In calculations, the pentaquark states are modeled by molecular-type interpolating currents: for particles with J = 5/2, a mixing current is used. We compare the results obtained in this work with the existing predictions of other theoretical studies. The predictions on the masses may shed light on experimental searches of the bottom pentaquarks.Article Citation - WoS: 31Citation - Scopus: 32Determination of the Quantum Numbers of Σb< Via Their Strong Decays(Amer Physical Soc, 2019) Aliev, T. M.; Azizi, K.; Sarac, Y.; Sundu, H.Recent experimental progress has led to the detection of many new hadrons. Very recently, the LHCb Collaboration announced the observation of two new Sigma(b)(6097)(+/-) states in the Lambda(0)(b)pi(+/-) invariant mass distribution, which are considered to be the excited states of the ground-state Sigma((*))(b) baryon. Although almost all of the ground-state baryons have been observed, the fact that only a limited number of excited states have been observed makes them intriguing. Understanding the properties of the excited baryons would improve our knowledge about the strong interaction, as well as the nature and internal structures of these baryons. To specify the quantum numbers of the Sigma(+/-)(b(6097)) states, we analyze their strong decays to Lambda(0)(b) and pi(+/-) within the light-cone QCD sum rules formalism. To this end, they are considered as possible 1P or 2S excitations of either the ground-state Sigma(b) baryon with J = 1/2 or the Sigma(b)* baryon with J = 3/2, and their corresponding masses are calculated. The results of the analyses indicate that the Sigma(b)(6097)(+/-) baryons are excited 1P baryons with quantum numbers J(P) = 3-/2.Article Citation - WoS: 10Citation - Scopus: 11Investigation of the Strange Pentaquark Candidate Pλψsð4338þ0 Recently Observed by Lhcb(Amer Physical Soc, 2023) Azizi, K.; Sarac, Y.; Sundu, H.The recently observed strange pentaquark candidate, P Lambda yso4338 thorn 0, is investigated to provide information about its nature and substructure. To this end, its mass and width through the decay channels P Lambda yso4338 thorn 0 -> J=y Lambda and P Lambda yso4338 thorn 0 -> ric Lambda are calculated by applying two- and three-point QCD sum rules, respectively. The state is considered as a Xi c D over bar meson-baryon molecular structure with spin-parity quantum numbers JP 1/4 1 -. The obtained mass, mP Lambda 2 yso4338 thorn 0 1/4 4338 130 MeV, and width, Gamma P Lambda yso4338 thorn 0 1/4 10.40 1.93 MeV, are consistent with the experimental data within the presented uncertainties. This allows us to assign a Xi c D over bar molecular structure of JP 1/4 1 - for the P Lambda yso4338 thorn 0 state.Article Citation - WoS: 19Citation - Scopus: 19Possible Molecular Pentaquark States With Different Spin and Quark Configurations(Amer Physical Soc, 2018) Azizi, K.; Sarac, Y.; Sundu, H.We investigate three possible pentaquark candidates, one of which contains a single charm quark and the other two contain triple charm quarks in their substructure. To this end we apply the QCD sum rule method and take into account both the positive and negative parity states corresponding to each possible pentaquark channel having spin 3/2 or 1/2. Insisting on the importance of identification of the members of the pentaquark family we obtain their spectroscopic parameters such as masses and residues. These parameters are the main inputs in the searches for their electromagnetic, strong, and weak interactions.
