82 research outputs found
Spectroscopy of the hidden-charm and tetraquarks
We calculate the spectrum of and
tetraquarks, where , and stand for light (), strange and charm
quarks, respectively, in a relativized diquark model, characterized by
one-gluon-exchange (OGE) plus confining potential. In the diquark model, a
() tetraquark configuration is made up of
a heavy-light diquark, (), and anti-diquark, (). According to our results, 13 charmonium-like observed states can be
accommodated in the tetraquark picture, both in the hidden-charm () and hidden-charm hidden-strange () sectors.Comment: Discussions extended, references adde
Heavy Quark Spin Symmetry Violating Hadronic Transitions of Higher Charmonia
In heavy quarkonia, hadronic transitions serve as an enlightened probe for
the structure and help to establish the understanding of light quark coupling
with a heavy degree of freedom. Moreover, in recent years, hadronic transitions
revealed remarkable discoveries to identify the new conventional heavy
quarkonia and extracting useful information about the so called "XYZ" exotic
states. In this contribution, we present our predictions for heavy quark spin
symmetry (HQSS) breaking hadronic transitions of higher and wave vector
charmonia based on our recently proposed model (inspired by Nambu-Jona-Lasinio
(NJL) model) to create light meson(s) in heavy quarkonium transitions. We also
suggest spectroscopic quantum numbers for several observed
charmoniumlike states. Our analysis indicates that the is most likely
to be a dominant state.Comment: Proceedings of the talk presented at "XVII International Conference
on Hadron Spectroscopy and Structure (Hadron2017)", 25-29 September 2017,
Salamanca, Spai
Tetraquark mass relations in quark and diquark models
We present new linear relations among the masses of S-wave tetraquarks with
either one flavour () or two (). Because the
relations are sensitive to the hidden-colour, spin, and spatial degrees of
freedom, comparison to experimental data can help to reveal the internal
structure of tetraquarks, and discriminate among different theoretical models.
Depending on the model, the relations are either exact, or valid in
perturbation theory, and a thorough comparison with existing literature
confirms their validity at the MeV level. Additionally, we explore the
connections among tetraquark models, and show how those with effective (quark
or diquark) masses are related to dynamical potential models. We also show how
the spectrum of diquark models is effectively a limiting case of (more general)
quark models, and in particular, that the diquark concept is most relevant in
the particular combination , where is much heavier than
.Comment: Published versio
Structure of tetraquarks and interpretation of LHC states
Motivated by recent experimental evidence for apparent
states at LHCb, CMS and ATLAS, we consider how the mass spectrum and decays of
such states can be used to discriminate among their possible theoretical
interpretations, with a particular focus on identifying whether quarks or
diquarks are the most relevant degrees of freedom. Our preferred scenario is
that and its apparent partner state are the tensor
and scalar states of an S-wave multiplet of states. Using tetraquark mass relations which are independent of (or
only weakly dependent on) model parameters, we give predictions for the masses
of additional partner states with axial and scalar quantum numbers.
Additionally, we give predictions for relations among decay branching fractions
to , , and
channels. The scenario we consider is consistent with existing experimental
data on , and our predictions for partner states and their
decays can be confronted with future experimental data, to discriminate between
quark and diquark models
Evaluation of anxiety and depression in chronic liver disease patients.
Objective: To evaluate the risk factors of anxiety and depression in chronic liver disease patientsMethodology: In this longitudinal study seven hundred fifty-five patients (mean age 51+ 5 years, 59% males). All the patients were suffering from chronic hepatitis B, chronic Hepatitis C, Alcoholic liver disease and non-alcoholic fatty stomach disease. Questionnaires were included anxiety, using the Hamilton depressing rating scale (HDRS) and Hamilton anxiety scale (HARS), including socio-demographic, health status and family support. The criteria for inclusion in the study were having liver disease from last 15 months. Clinical functional and psychological assessments were performed.Results: In this study patients with depression was 59.3%, with anxiety 17.4% patients and both anxiety and depression were noted in 36.7% patients. After measuring and calculating all the variables score of depression and anxiety were recorded. A higher HDRS score was noted in patients older than 46 years (p=0.024). Patients with gastrointestinal bleeding had a prominent higher score of anxiety than those without bleeding (p=0.019). A higher HARS score was present in the women (p=0.011), unemployed patients (p=0.009) and those with alcoholic liver disease (p=0.006). There was direct correlation between the duration of disease and the value of HDRA and HARS score.Conclusion: In the chronic liver disease patients’ depression and anxiety are increasingly high with passage of time, gastrointestinal bleeding and unemployment. Increased prevalence of relax by patients are more likely to be due to the low acceptance of disease prognosis
Spectroscopy and decays of the fully-heavy tetraquarks
We discuss the possible existence of the fully-heavy tetraquarks. We
calculate the ground-state energy of the bound state, where
stands for the bottom quark, in a nonrelativistic effective field theory
framework with one-gluon-exchange (OGE) color Coulomb interaction, and in a
relativized diquark model characterized by OGE plus a confining potential. Our
analysis advocates the existence of uni-flavor heavy four-quark bound states.
The ground state tetraquark mass is predicted to be
~GeV. Mass inequality relations among the lowest
state, where , and the corresponding heavy
quarkonia are presented, which give the upper limit on the mass of ground state
. The possible decays of the lowest are
highlighted, which might provide useful references in the search for them in
ongoing LHC experiments, and its width is estimated to be a few tens of MeV.Comment: Version accepted for publication in Eur. Phys. J.
Multiplet Revisited: Ultrafine Mass Splitting and Radiative Transitions
Invoked by the recent CMS observation regarding candidates of the
multiplet, we analyze the ultrafine and mass splittings among
multiplet in our unquenched quark model (UQM) studies. The mass difference of
and in multiplet measured by CMS collaboration
( MeV) is very close to our theoretical prediction
( MeV). Our corresponding mass splitting of and
enables us to predict more precisely the mass of to be
() MeV. Moreover, we predict ratios of the radiative decays of
candidates, both in UQM and quark potential model. Our
predicted relative branching fraction of
is one order of magnitude smaller than , this naturally explains
the non-observation of in recent CMS search. We hope these
results might provide useful references for forthcoming experimental searches
An in silico approach to analyze HCV genotype-specific binding-site variation and its effect on drug-protein interaction
Genotype variation in viruses can affect the response of antiviral treatment. Several studies have established approaches to determine genotype-specific variations; however, analyses to determine the effect of these variations on drug-protein interactions remain unraveled. We present an in-silico approach to explore genotype-specific variations and their effect on drug-protein interaction. We have used HCV NS3 helicase and fluoroquinolones as a model for drug-protein interaction and have investigated the effect of amino acid variations in HCV NS3 of genotype 1a, 1b, 2b and 3a on NS3-fluoroquinolone interaction. We retrieved 687, 667, 101 and 248 nucleotide sequences of HCV NS3 genotypes 1a, 1b, 2b, and 3a, respectively, and translated these into amino acid sequences and used for genotype variation analysis, and also to construct 3D protein models for 2b and 3a genotypes. For 1a and 1b, crystal structures were used. Drug-protein interactions were determined using molecular docking analyses. Our results revealed that individual genotype-specific HCV NS3 showed substantial sequence heterogeneity that resulted in variations in docking interactions. We believe that our approach can be extrapolated to include other viruses to study the clinical significance of genotype-specific variations in drug-protein interactions
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