• Dilip Kumar

Articles written in Pramana – Journal of Physics

• An on-line TDC-312 computer-controlled neutron diffractometer

The design and fabrication of an indigenous on-line computer controlled four-circle neutron diffractometer at the CIRUS reactor in Trombay are described. The diffractometer has an 18 in dia full-circle crystal-orienter which is sturdy enough to carry a cryostat. Three crystal orientation angles χ, φ and ω and the detector angle 2θ can be set to an accuracy of 0·01°. The four angle shafts are driven through precision worm-gears by SCR-controlled DC motors and their instantaneous positions sensed by optical digitizers. The diffractometer is interfaced to an ECIL TDC-312 computer system consisting of the CPU with 4K-memory, ASR-35 teletype, X-Y plotter and the digital input/output system (DIOS). The DIOS which operates under program control is a real-time peripheral device used to exchange information in digital form between the computer and the diffractometer. A software package consisting of over 40 useroriented teletype commands has been developed for on-line control and automatic data-acquisition.

• B and collider physics: Working group report

This report summarises the work done during WHEPP-6 (Institute of Mathematical Sciences, Chennai, India, Jan 3–15, 2000) in Working group on ‘B and collider physics’.

• Search for the Higgs boson in the $H \rightarrow WW \rightarrow \ell \nu jj$ decay channel in $pp$ collisions at $\sqrt{s} = 7$ TeV with the ATLAS detector

A search for a Higgs boson has been performed in the $H \rightarrow WW \rightarrow \ell \nu jj$ channel using 1.04 fb-1 of $pp$ collision data at $\sqrt{s} = 7$ TeV recorded with the ATLAS detector at the Large Hadron Collider. No significant excess of events is observed over the expected Standard Model (SM) background and limits on the Higgs boson production cross-section are derived for a Higgs boson mass in the range 240 GeV $&lt; m_{\text{H}} &lt; 600$ GeV. The best sensitivity is obtained for $m_{\text{H}} = 400$ GeV, where the 95% confidence level upper bound on the cross-section for $H \rightarrow WW$ production is 3.1 pb, or 2.7 times the Standard Model prediction.

• A mini review on CP-violating minimal supersymmetric Standard Model Higgs

We discuss the present status of the Higgs sector of the CP-violating minimal supersymmetric Standard Model (CPVMSSM). In the Standard Model (SM) of particle physics, the only source of CP violation is the complex phase in the Cabibbo–Kobayashi–Maskawa (CKM) matrix. By now we all know that this singlephase is not large enough to explain the observed baryon asymmetry of our Universe. Hence, one require additional sources of CP violation. The MSSM with several complex phases is one such scenario. The tree-level CP invariance of the MSSM Higgs potential is broken at one-loop level in the presence of complex phases in the MSSM Lagrangian. The presence of these additional phases modifies Higgs masses, mixings and couplings significantly. These additional phases have non-trivial impact on several low-energy observables; like the electric dipole moments (EDMs) of atoms and molecules, the CP asymmetry in rare b-decays etc. We first present a brief outline of the CPVMSSM Higgs sector, and then discuss the current limits/bounds obtained from the measurementsof several low-energy observables. We also comment on the current bounds coming from the high-energy collider experiments, specially the Large Electron Positron (LEP) Collider and the ongoing Large Hadron Collider (LHC) at the CERN.

• # Pramana – Journal of Physics

Current Issue
Volume 93 | Issue 6
December 2019

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019