D. Ghosh

Supermassive magnetic monopoles flux from the oldest mica samples

Here we report the results of an experimental search for the stored monopole tracks in our 9 108 y old mica sample. We selected a few pieces of mica sample etched with hydrofluoric acid and scanned in transmitted light under polarizing microscope to search for etch pits originating from the lattice defects produced in mica due to elastic nuclear collisions of nucleus-monopole boundpair. The absence of any etch pit characterizing monopole track in our most oldest sample searched so far sets an upper limit of 10-16 to 10-18 cm-2 sr-1 s-1 on the flux of the supermassive monopoles having velocity 3 10-4 to 1.5 10-3 c, which is slightly lower than the results of Price et al.

Observation of hot and cold events in the 12C-emulsion interaction at 4.5 GeV/c per nucleon-a signal for quark matter formation?

The authors present a study of the transverse momentum distribution of relativistic alpha particles emerging from the interaction of 12C and emulsion at 4.5 GeV/c per nucleon. A large statistics study of 1200 events when compared with the Maxwell-Boltzmann distribution reveals the existence of two temperatures, a hot and a cold, since a single Maxwell-Boltzmann distribution cannot fit the peak and the tail simultaneously. This yield of two distinctly different temperatures in the fragmentation region may be interpreted as a possible signal for the formation of a quark-gluon plasma.

Evidence of Fractality in Proton Emission in Nucleus-Nucleus Interactions

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.

Evidence of different pion coherence zones for 'hot' and 'cold' events in relativistic heavy-ion interaction

A comparison of the transverse momentum (PT) distribution of the alpha particles emitted as projectile fragments from the 12C-emulsion interaction at 4.5 GeV c-1 with the double Maxwell-Boltzmann distribution yields two temperature in the projectile fragmentation region (10 MeV and 40 MeV). This work reports a study on the coherence of pion production for two classes of events-cold (10 MeV) and hot (40 MeV). The data show an interesting observation-in the case of cold events pions are produced coherently in a specific pseudo-rapidity region, whereas pion production is extremely incoherent for hot events in that zone; it is coherent in a different pseudo-rapidity region.

Unpacking sustainabilities in diverse transition contexts: : solar photovoltaic and urban mobility experiments in India and Thailand

It is generally accepted that the concept of sustainability is not straightforward, but is subject to ongoing ambiguities, uncertainties and contestations. Yet literature on sustainability transitions has so far only engaged in limited ways with the resulting tough questions around what sustainability means, to whom and in which contexts. This paper makes a contribution to this debate by unpacking sustainability in India and Thailand in the context of solar photovoltaic and urban mobility experimentation. Building on a database of sustainability experiments and multicriteria mapping techniques applied in two workshops, the paper concludes that sustainability transition scholarship and associated governance strategies must engage with such questions in at least three important ways. First, there is a need for extreme caution in assuming any objective status for the sustainability of innovations, and for greater reflection on the normative implications of case study choices. Second, sustainability transition scholarship and governance must engage more with the unpacking of uncertainties and diverse possible socio-technical configurations even within (apparently) singular technological fields. Third, sustainability transition scholarship must be more explicit and reflective about the specific geographical contexts within which the sustainability of experimentation is addressed.

Non-statistical fluctuation in compound multiplicity distribution in ultrarelativistic nuclear collisions: Factorial correlator study

An investigation of non-statistical fluctuation of the compound multiplicity spectrum in 32S–AgBr interactions at 200 AGeV in terms of factorial correlators is presented. It is observed that the correlated moments increase with decrease in bin–bin separation D, following a power law, which suggests the presence of an intermittent nature of self-similar dynamical fluctuation patterns in the compound multiplicity spectrum. The data also support the α model of intermittency.

Multiplicity Characteristics of Symmetric and Asymmetric Heavy-Ion Interactions at 4.5 A GeV/c

This letter presents a systematic analysis of multiplicity data in limited regions of phase space in symmetric (12C-C/N/O) and asymmetric (24Mg-Ag/Br) heavy-ion interactions at 4.5A GeV/c. It is observed that in both types of interactions the multiplicity distribution of produced charged particles can be well fitted to the newly prescribed negative binomial (NB) law, the detailed characteristics of which are also investigated. Also, for the first time a universality is observed in the behaviour of entropy production in symmetric and asymmetric nuclear collisions if the incident momentum per nucleon is kept constant.

Fluctuation of fluctuations in pionisation: Target excitation dependence

This paper presents some interesting and informative results of experimental investigation on target excitation dependence of fluctuation of fluctuations studies on produced pions emitted in 16O-AgBr interactions at 60 AGeV and 32S-AgBr interactions at 200 AGeV. A search for the possible signature of chaotic behavior of multiparticle production in nucleus-nucleus collision has been performed with the help of entropy index, μq. To study the target excitation dependence of the chaotic behavior, the whole dataset is divided into subsamples having different number of recoil target protons which may be considered as a measure of target excitation.

Analysis ofPT spectrum of projectile fragments in heavy-ion interactions. Identification of collective flow of nuclear matter

SummaryTransverse-momentum data of the projectile fragments are analysed to identify the presence of collective flow of nuclear matter in symmetric (16O-CNO at 2.1A GeV and12C-CNO at 4.5A GeV/c) and asymmetric (24Mg−AgBr at 4.5A GeV/c) heavy-ion interactions, adapting the method proposed by Danielewicz and Odyniec. A comparison of the data with Monte-Carlo-simulated values gives a positive indication of collective flow in each case.

Study of transverse momentum spectrum of proton projectile fragments in 4.5A GeV/c12C-Emulsion interactions. Evidence of a single temperature

SummaryThis work reports a study of transverse momentum distribution of relativistic proton fragments emerging from the interaction of12C with nuclear emulsion at 4.5A GeV/c energy. A comparison of transverse momentum spectrum with the Maxwell-Boltzmann distribution reveals a temperature of about 8 MeV. This observation does not agree with the results obtained by a similar analysis with relativistic alpha projectile fragments where there was a clear indication of two different temperatures (10 MeV and 40 MeV).RiassuntoQuesto lavoro riporta uno studio di distribuzione di momento trasverso di frammenti di protoni relativistici che emergono dall’interazione di12C con emulsione nucleare ad energia 4.5A GeV/c. Un confronto dello spettro di momento trasverso con la distribuzione di Maxwell-Boltzmann rivela una temperatura di circa 8 MeV. Questa osservazione non si accorda con i risultati ottenuti da un’analisi simile con frammenti di proiettili alfa relativistici dove è emersa una chiara indicazione di due diverse temperature (10 e 40 MeV).РезюмеВ работе приводятся результаты исследования распределения поперечных импульсов релятивистских протонных фрагментов, образующихся при взаимодействии12С с импульсом 4.5А ГэВ/с с ядерной имульсией. Сравнение спектров поперечных импульсов с распределением Максвелла-Больцмана обнаруживает температуру порядка 8 МэВ. Этот результат не согласуется с данными аналогичного анализа для релятивистских альфа-фрагментов, где были обнаружены две различных температуры (10 МэВ и 40 МэВ).