P. Ghosh

Study on fractility in nucleus-nucleus interaction at a few GeV/c

Abstract The scaled factorial moments, F q and fractal moments, G q have been measured and their power law variation as a function of size of the pseudorapidity interval has been studied in the central region of the pseudorapidity distribution of the produced charged particles in quasi-central and central collisions of 16 O + Ag Br at 2.1 GeV c per nucleon and 24 Mg + Ag Br at 4.5 GeV c per nucleon. The smooth spectral function f ( α q ), characterizing the fluctuation in the pseudorapidity distribution and the generalised dimensions D q have been derived from G q moments. The analyses reveal a self-similarity in multiparticle production in nucleus-nucleus interactions at an incident momentum of a few GeV/ c per nucleon. Interesting observations can be very effective in establishing multifractality in multiparticle production at this energy range.

Negative binomial multiplicity distribution in proton-proton collisions in limited pseudorapidity intervals at LHC up to

intervals. We analyze multiplicity distribution data of proton-proton collisions at LHC energies as measured by the Compact Muon Solenoid (CMS) experiment in terms of characteristic parameters of the Negative Binomial Distribution (NBD) function that has played a significant role in describing multiplicity distribution data of particle production in high energy physics experiments, in the pre-LHC energy-range, in various kinds of collisions for a wide range of collision energy and for different kinematic ranges. Beside a single NBD, we apply the formalism of weighted superposition of two NBDs to examine if the multiplicity distribution data of CMS could be better explained. The weighted superposition of two NBDs indeed explain the distribution data better at the highest available LHC energy and in large interval of phase space. The two-NBD formalism further reveals that the energy invariance of the multiplicity distribution of the “soft” component of particle production in hadronic collisions is valid at LHC also, as it is at RHIC and Tevatron. We analyze the data further in terms of clan parameters in the framework of the two-NBD model. PACS numbers: 13.85.Hd

\sqrt{s} = 7

Abstract A honeycomb detector consisting of a matrix of 96 closely packed hexagonal cells, each working as a proportional counter with a wire readout, was fabricated and tested at the CERN PS. The cell depth and the radial dimensions of the cell were small, in the range 5– 10 mm . The appropriate cell design was arrived at using GARFIELD simulations. Two geometries are described illustrating the effect of field shaping. The charged particle detection efficiency and the preshower characteristics have been studied using pion and electron beams. Average charged particle detection efficiency was found to be 98%, which is almost uniform within the cell volume and also within the array. The preshower data show that the transverse size of the shower is in close agreement with the results of simulations for a range of energies and converter thicknesses.

TeV and the clan model

We investigate the spacetime of a global monopole in a five-dimensional spacetime in the presence of the cosmological term. Also the gravitational properties of the monopole solution are discussed.

A honeycomb proportional counter for photon multiplicity measurement in the ALICE experiment

Factorial Correlators (FCs), a tool for the test of “intermittency” in multiparticle production in high energy physics, has not been given much attention, compared to the efforts towards understanding the phenomenon in terms of scaled factorial moments. So far, only hadron-hadron data of NA22 collaboration and nucleus-nucleus data of EMU01 collaboration have been analyzed in terms of FCs. However, the present situation of intermittency study demands thorough exploitation of all the available tools for better understanding of the phenomenon. In this article we present the analysis of particle production data of hadron-nucleus interaction at 200 GeV/c in terms of FCs. The results of the analysis show a consistency with the prediction of α-model for the existence of “intermittency.”

Higher dimensional global monopole with cosmological term

The method of scaled factorial moments is used to study non-statistical fluctuations present in the emission process of the medium-energy protons, emitted in nucleus-nucleus interactions, in terms of their emission angle (?). The investigation has been done with our data of 24Mg-Ag/Br interaction at 4.5?GeV/c/n and 16O-Ag/Br interaction at 2.1?GeV/n. Corrections have been made for the non-uniformity of the distribution of the variable used for the purposes of analysis. A power law growth of the corrected moments with decreasing bin size suggests an intermittent behaviour in both the cases. Multifractal analysis in terms of fractal moments, Gi, has also been performed, which reveals hint of multifractality in the emission process.

INTERMITTENCY IN HADRON-NUCLEUS INTERACTIONS AT 200 GeV/c IN TERMS OF FACTORIAL CORRELATORS

We study the system-size dependence of Knudsen number, a measure of degree of thermalization, for hadron resonance gas that follows the Lattice-QCD equation of state at zero chemical potential. A comparison between Knudsen numbers for the AuAu collisions at RHIC and the hadron gas of size similar to the size of high-multiplicity pp events at LHC, reassures the applicability of hydrodynamics in interpreting the features of particle production in high-multiplicity pp events.

Evidence of Fractality in Proton Emission in Nucleus-Nucleus Interactions

Sir, Posterior reversible encephalopathy syndrome (PRES) is a clinico-radiological entity characterized by seizure, altered sensorium, visual disturbance and nausea, and vomiting, along with characteristic neuroimaging findings. Magnetic resonance imaging (MRI) often shows bilateral, symmetric areas of white matter edema predominantly in occipital and posterior parietal lobes. Autoimmune diseases are associated with 8–10% of PRES cases. PRES has been reported in patients with systemic lupus erythematosus (SLE). On the other hand, drugs, chiefly chemotherapeutic agents, immunosuppressive agent, and monoclonal antibodies including rituximab, are also considered as possible etiological agents. We report a patient of lupus nephritis who developed PRES following third dose of rituximab infusion. A 17-year-old female was admitted with a flare of lupus nephritis. She was diagnosed as SLE with nephritis (class IV-A) about 21⁄2 years previously and received cyclophosphamide according to NIH protocol followed by maintenance therapy with mycophenolate mofetil along with corticosteroid. She responded well but developed the current episode of nephritis flare while on regular maintenance therapy. Urine analysis showed active sediments with nephrotic range proteinuria (9.2 g/24 hours). She was started with rituximab (375mg/m of body surface area/week). Twelve hours after the third dose of rituximab she developed repeated attacks of convulsions, visual disturbances in the form of blurring of vision, and she was stuporous (Grady coma scale II and Glasgow coma scale 9). Blood pressure was 130/98mmHg. Plantar reflexes were extensor bilaterally. No focal neurological signs were present. Fundoscopy and cerebrospinal fluid studies were normal. MRI of the brain was consistent with a diagnosis of PRES (Figure 1). She responded to conservative management and follow-up MRI after four weeks was normal. She was not given the fourth dose of rituximab. Approximate prevalence of PRES among SLE patients is 0.69%. PRES is found more commonly among Asian patients. Most of the patients are female with highly active disease and renal involvement. Most of them are also hypertensive (91.7%). In an Indian cohort of 13 SLE patients, six had PRES as a part of their initial presentation of lupus. PRES is more common among young lupus patients in the early part of the disease. Almost 90% patients show full recovery. Our patient had most of these clinical parameters implicated in the development of PRES except for significant hypertension. PRES following rituximab therapy has also been documented in the literature. Mavragani et al. reported PRES in a lupus nephritis patient following a third dose of rituximab infusion. The exact pathogenesis of PRES following rituximab is not definitely known. Hypertensive crisis seen in few patients following rituximab therapy may be an important factor. However, there was no such event in our patient. Endothelial activation by rituximab through CD20 binding may be another possible mechanism. In this patient it was difficult to determine whether PRES was due to disease or drug. However, absence of significant hypertension, normal fundoscopic finding, and a clear temporal association between symptom development and rituximab infusion prompted us to withhold rituximab. We report this case as an example of a

Thermalization in a small hadron gas system and high-multiplicity pp events

Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700 064, India(Dated: March 4, 2014)Measured multiplicity distributions of primary charged particles produced in the forward rapidityregion of the proton−proton (pp) collisions at the centre-of-mass energy,√s = 7 TeV at the LargeHadron Collider (LHC) have been analyzed in terms of the Negative Binomial Distribution (NBD)function. Like the multiplicity distributions in the mid-rapidity region for the pp collisions at√s =7 TeV, the distributions for the minimum bias events in the forward region also are better describedwith the superposition of two-NBDs, as proposed by a two-component model of particle productionfrom two processes, the ”soft” and the ”hard”. However, the multiplicity distribution for the”hard-QCD” events in a large pseudorapidity window does not oblige the two-component model.

Posterior reversible encephalopathy syndrome in a patient with lupus nephritis on rituximab therapy: a challenge to find the offender

We study the gravitational properties of a global monopole in (D=d+2)-dimensional space–time in the presence of electromagnetic field.We study the gravitational properties of a global monopole in