Spectroscopy of the hidden-charm [qc][qˉcˉ][qc][\bar q \bar c] and [sc][sˉcˉ][sc][\bar s \bar c] tetraquarks

We calculate the spectrum of $q\bar q c \bar c$ and $s\bar s c \bar c$ tetraquarks, where $q$, $s$ and $c$ stand for light ($u,d$), strange and charm quarks, respectively, in a relativized diquark model, characterized by one-gluon-exchange (OGE) plus confining potential. In the diquark model, a $q\bar q c \bar c$ ($s\bar s c \bar c$) tetraquark configuration is made up of a heavy-light diquark, $q c$ ($sc$), and anti-diquark, $\bar q \bar c$ ($\bar s \bar c$). According to our results, 13 charmonium-like observed states can be accommodated in the tetraquark picture, both in the hidden-charm ($q\bar q c \bar c$) and hidden-charm hidden-strange ($s\bar s c \bar c$) 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 $S$ and $D$ 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 $(^{2S+1}L_J)$ for several observed charmoniumlike states. Our analysis indicates that the $Y(4360)$ is most likely to be a $3D$ dominant state.Comment: Proceedings of the talk presented at "XVII International Conference on Hadron Spectroscopy and Structure (Hadron2017)", 25-29 September 2017, Salamanca, Spai

Oxidoreductases and RNA Degradosome Controlling Virulence-Associated Traits of Salmonella enterica serovar Typhimurium

The oxidative stress response is a fundamental and primitive mode of innate immune defense in nearly all forms of life. The host oxidative stress response becomes truly important and effective especially against intracellular pathogens such as Salmonella. Pathogens have evolved diverse mechanisms to withstand the oxidative responses. These include the use of oxidoreductases to neutralize oxidative products and repair oxidative damages, rapid alteration in their transcriptome and diversion of such oxidative products in cellular signaling, for their survival and successful infection. In the first study in this thesis, we have introduced the putative ScsABCD oxidoreductases of the thioredoxin superfamily for their role in oxidative stress tolerance and in virulence of S. Typhimurium. We demonstrated that ScsABCD proteins are dispensable for invasion in cultured epithelial cells under normal invasive conditions, although ScsABCD acts as a suppressor of SPI-1 mediated invasion upon oxidative stress. Our results have further shown a functional association between ScsABCD and thiroredoxin 1 (TrxA) oxidoreductase of S. Typhimurium. In this, we demonstrated that absence of ScsABCD restored the invasiveness of a trxA mutant in epithelial cells and its virulence in C. elegans. (Paper I). Next, we present the analyses on the role of periplasmic Dsb oxidoreductase system in S. Typhimurium’s biofilm-development, specifically under redox stress. In this, we show that DsbA and DsbB act as suppressors of rdar-morphotype development and affect biofilm-regulation using either Csg-dependent or -independent mechanism, respectively. Our results further reveal that oxidative stress abrogates rdar-morphotype of S. Typhimurium, whereas reductive stress reduces rdar-morphotype with concomitant plentiful release of extracellular slimy material containing, notably, the extracellular DNA (eDNA). Furthermore, we have demonstrated the oxidative recovery of swimming motility defects of a dsbA mutant. (Paper II). Finally, we have demonstrated that exoribonuclease; PNPase and its genetic associate membrane lipoprotein NlpI constitute an operon and are functionally connected (Papers III and IV). PNPase was required for rdar-morphotype development whereas, NlpI suppresses the biofilm formation. In addition, we established the association of PNPase with c-di-GMP metabolism in biofilm regulation. Moreover, we showed that both PNPase and NlpI are required, independently, for cold adaptation of S. Typhimurium

Tetraquark mass relations in quark and diquark models

We present new linear relations among the masses of S-wave tetraquarks with either one flavour ($QQ \bar Q \bar Q$) or two ($QQ\bar q \bar q$). 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 $QQ\bar q \bar q$, where $Q$ is much heavier than $\bar q$.Comment: Published versio

Structure of cccˉcˉcc \bar c \bar c tetraquarks and interpretation of LHC states

Motivated by recent experimental evidence for apparent $cc\bar c \bar c$ 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 $X(6600)$ and its apparent partner state $X(6400)$ are the tensor $(2^{++})$ and scalar $(0^{++})$ states of an S-wave multiplet of $cc\bar c \bar c$ 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 $J/\psi J/\psi$, $J/\psi \eta_c$, $\eta_c\eta_c$ and $D^{(*)} \bar{D}^{(*)}$ channels. The scenario we consider is consistent with existing experimental data on $J/\psi J/\psi$, and our predictions for partner states and their decays can be confronted with future experimental data, to discriminate between quark and diquark models

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 $bb \bar b \bar b$ bound state, where $b$ 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 $bb\bar b\bar b$ tetraquark mass is predicted to be $(18.72\pm0.02)$~GeV. Mass inequality relations among the lowest $QQ\bar{Q}\bar{Q}$ state, where $Q\in \{c, b\}$, and the corresponding heavy quarkonia are presented, which give the upper limit on the mass of ground state $QQ\bar{Q}\bar{Q}$. The possible decays of the lowest $bb\bar{b}\bar{b}$ 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.

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