We study some rare decays of B meson involving the quark level transitionin the scalar leptoquark model. We constrain the leptoquark parameter space using the recently measured branching ratios of B s,d → µ + µ − processes. Using such parameters, we obtain the branching ratios, direct CP violation parameters and isospin asymmetries in B → Kµ + µ − and B → πµ + µ − processes. We also obtain the branching ratios for some lepton flavour violating decays B → lWe find that the various anomalies associated with the isospin asymmetries of B → Kµ + µ − process can be explained in the scalar leptoquark model.

Nosocomial infections caused by Acinetobacter baumannii often prove difficult to treat owing to their multiple drug resistance. Carbapenems play a pivotal role in the management of severe Acinetobacter infections. However, reports of carbapenem resistance have been increasing alarmingly due to production of a variety of carbapenemases including metallo-b-lactamases (MBLs). This study investigated by both phenotypic and genotypic assays the prevalence of MBLs in a total of 55 A. baumannii strains isolated from a South Indian tertiary care hospital. Random amplified polymorphic DNA (RAPD) genotyping and antimicrobial susceptibility testing for nine clinically relevant antibiotics was done for characterization of isolates. Phenotypic expression of MBLs was examined by a simple double disc synergy (DDS) test, and the presence of the most frequent MBL coding genes, bla IMP1 and bla VIM2 , was checked by PCR. RAPD analysis generated six clusters of isolates and there was very little correlation between RAPD clusters and resistant profiles. Most of the isolates showed complete or high resistance to imipenem (100 %), meropenem (89 %), amikacin (80 %), cefotaxime (89 %) and ciprofloxacin (72 %). In addition, 44 % of isolates showed a high MIC level (¢16 mg ml "1 ) for meropenem. Thirty-nine isolates (70.9 %) were positive for MBL production by the DDS test while bla IMP1 gene amplification was seen only in 23 isolates (42 %). Interestingly, none of the isolates showed amplification of bla VIM2 . Further investigations on DDS-positive/PCR-negative isolates by spectrophotometric assay showed MBL activity in most of the isolates, suggesting involvement of other genes. The high incidence of isolates possessing MBL activity in the present study represents an emerging threat of complete resistance to carbapenems among Acinetobacter spp. in India.

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Recently the B factories BaBar and Belle as well as the LHCb experiment have reported several anomalies in the semileptonic B meson decays such as R K and R D ( * ) etc. We investigate these deviations by considering the vector leptoquarks relevant for both b → sl + l − and b → clν l transitions. The leptoquark parameter space is constrained by using the experimentally measured branching ratios of B s → l + l − ,B → X s l + l − (νν) and B + u → l + ν l processes. Using the constrained leptoquark couplings, we compute the branching ratios, forward-backward asymmetries, τ and D * polarization parameters in theB → D ( * ) lν l processes. We find that the vector leptoquarks can explain both R D ( * ) and R K anomalies simultaneously. Furthermore, we study the rare leptonic B * u,c → lν decay processes in this model.

We study the effect of scalar leptoquarks on the exclusive rare B meson decaysB 0 d → K * 0 (→ K − π + ) l + l − in the full kinematically accessible physical region. We work out the constraints on leptoquark parameter space using the measured branching ratio of B s → µ + µ − process by the CMS and LHCb collaborations. We compute the branching ratio, forward-backward asymmetry and isospin asymmetry distribution using the constrained parameter space. We also look into various form factor independent and CP violating observables in the scalar leptoquark model.