118579192
Multiplicity distributions of shower particles and target fragments in 84Kr36–emulsion interactions at 1 GeV per nucleon
This article focuses on multiplicity distributions of shower particles and target fragments for interaction of 84Kr36 with NIKFI BR-2 nuclear emulsion target at kinetic energy of ~1 GeV per nucleon. Experimental multiplicity distributions of shower particles, grey particles, black particles and heavily ionization particles are well described by multi-component Erlang distribution of multi-source thermal model. We have observed a linear correlation in multiplicities for the above mentioned particles or fragments. Further experimental studies have shown a saturation phenomenon in shower particle multiplicity with the increase of target fragment multiplicity.
123203919
Factorization of fragmentation cross-sections in heavy-ion collisions at 1A GeV
Fe-, Kr- and Xe-induced heavy-ion reactions at ~ 1 A GeV show factorization in the production cross-sections only for light fragments. Both "strong" and "weak" factorization are found for light fragments. The cross-sections of these fragments are described in detail within the prescription of cold breakup of spectator residues.
119107308
Hadron spectra in p+p collisions at RHIC and LHC energies
We present the systematic analysis of transverse momentum (pT) spectra of identified hadrons in p+p collisions at Relativistic Heavy Ion Collider ( and 200 GeV) and at Large Hadron Collider (LHC) energies (, 2.76 and 7.0 TeV) using phenomenological fit functions. We review various forms of Hagedorn and Tsallis distributions and show their equivalence. We use Tsallis distribution which successfully describes the spectra in p+p collisions using two parameters, Tsallis temperature T which governs the soft bulk spectra and power n which determines the initial production in partonic collisions. We obtain these parameters for pions, kaons and protons as a function of center-of-mass energy . It is found that the parameter T has a weak but decreasing trend with increasing . The parameter n decreases with increasing which shows that production of hadrons at higher energies are increasingly dominated by point like qq scatterings. Another important observation is with increasing , the separation between the powers for protons and pions narrows down hinting that the baryons and mesons are governed by same production process as one moves to the highest LHC energy.
118409510
Characteristics of alpha projectile fragments emission in interaction of nuclei with emulsion
The properties of the relativistic alpha fragments produced in interactions of 84Kr at around 1 A GeV in nuclear emulsion are investigated. The experimental results are compared with the similar results obtained from various projectiles with emulsion interactions at different energies. The total, partial nuclear cross-sections and production rates of alpha fragmentation channels in relativistic nucleus-nucleus collisions and their dependence on the mass number and initial energy of the incident projectile nucleus are investigated. The yields of multiple alpha fragments emitted from the interactions of projectile nuclei with the nuclei of light, medium and heavy target groups of emulsion-detector are discussed and they indicate that the projectile-breakup mechanism seems to be free from the target mass number. It is found that the multiplicity distributions of alpha fragments are well described by the Koba-Nielsen-Olesen (KNO) scaling presentation. The mean multiplicities of the freshly produced or newly created charged secondary particles, normally known as shower and secondary particles associated with target in the events where the emission of alpha fragments were accompanied by heavy projectile fragments having Z ≥ 3 seem to be constant as the alpha fragments multiplicity increases, and exhibit a behavior independent of the alpha fragments multiplicity.
119072934
Transverse mass spectra and scaling of hadrons at RHIC and LHC energies
We present a systematic study of transverse mass spectra ($m_T$) of mesons and baryons at RHIC and LHC energies. In an earlier study, it was shown that all the mesons produced in p+p and d+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV follow $m_T$ scaling while in Au+Au collisions at same energy the mesons with strange and charm quark contents do not follow $m_T$ scaling which can be attributed to medium modifications. 
We extend this study for baryons produced in all above colliding systems at $\sqrt{s_{NN}}$ = 200 GeV. Although all available baryon spectra behave differently from mesons but are found to scale with protons for both p+p and d+Au collisions. In case of Au+Au collisions, the strange baryons behave differently from protons. 
This study has also been performed on the meson spectra in p+p collisions at 62.4 GeV which lies in between the highest RHIC energy and SPS energy where the $m_T$ scaling was first observed and we arrive at same conclusions as those at 200 GeV. 
We test the $m_T$ scaling at LHC with the first meson spectra measured in p+p collisions at 900 GeV and find that the $m_T$ spectra of kaons and $\phi$ do not scale with pions. Thus $m_T$ scaling which was working well up to p+p collisions at 200 GeV seems to be broken. Here we use all data measured in the mid rapidity region. Baryon to meson ratio is studied as a function of $m_T$, at different energies and for different systems and is found that this ratio for p+p at 900 GeV is quite different from that in p+p collisions at RHIC energies.
117487117
The TEXONO research program on low-energy neutrino and astroparticle physics
AbstractThis article reviews the research program and efforts of the TEXONO Collaboration on neutrino and astroparticles. The main program is on reactor-based low-energy neutrino physics at the Kuo-Sheng Power Plant in Taiwan. The facilities of the laboratory are described. A limit on the neutrino magnetic moment of μν(
$$\bar \nu _e $$
) < 1.3 × 10−10 μB at 90% C.L. has been achieved from measurements with a high-purity germanium detector. Other research programs at Kuo-Sheng are surveyed.
56310271
Study of the shell effect on nuclear dissipation via neutron multiplicity measurement
Experimental neutron multiplicity data has been fitted using the Kramers' fission width, in statistical model calculations with and without inclusion of shell corrections in nuclear level density, nuclear masses and fission barrier. It has been found that the magnitude of dissipation strength changes to a large extent with inclusion of shell corrections in different ingredients of the statistical model. These observations clearly demonstrate the importance of shell corrections in statistical model calculations.
17616577
Bhabha’s contributions to elementary particle physics and cosmic rays research
Bhabha’s scientific research contributions are descibed in the context of his life and contemporary science. During the Cambridge period (1927–1939), he worked in positron theory (Bhabha scattering), cosmic rays (Bhabha-Heitler theory of cosmic ray showers, prediction of heavier electrons) and meson theory. In Bangalore during 1939–1945, he worked on classical relativistic spinning particles (Bhabha-Corben equations), meson theory and initiated experimental work in cosmic rays in India. He then founded Tata Institute of Fundamental Research in 1945 at Bombay and moved there. Here he started work on relativistic wave equations (Bhabha equations.). He also initiated India’s nuclear energy programme in 1948 and this was his main preoccupation later.
118649782
Unitarity restrictions on meson-nucleon helicity-flip amplitudes and slope of the diffraction peak
SummaryWe generalize the MacDowell-Martin bound on the slope parameterbA for the spinless case to the case of spin-0-spin-1/2 elastic scattering with parity conservation. We give the optimal answer for all energies as well as the simpler (slightly weaker) bound

$$cb^A \geqslant \frac{{\sigma _{tot}^2 }}{{36\pi \sigma _{el} }}\left[ {\sqrt {1 + \frac{{9\pi \sigma _{el} }}{{4k^2 \sigma _{tot}^2 }}} + 1} \right] - \frac{1}{{4k^2 }} (k = c.m. momentum).$$

 Here the superscript A refers to the absorptive-part contribution. We also obtain unitarity restrictions on the helicity-flip amplitude

$$cf_{ + - }^A (t)/\sqrt { - t} |_{t = 0} $$

 in terms ofσtot,σel, andbA(s).RiassuntoSi generalizza il limite di McDowell- Martin sul parametro di inclinazionebA per il caso privo di spin fino al caso dello seattering elastico tra spin nullo e spin 1/2 con conservazione della parità. Si dà una risposta ottimale per tutte le energie così come per il limite più semplice (leggermente più debole)

$$cb^A \geqslant \frac{{\sigma _{tot}^2 }}{{36\pi \sigma _{el} }}\left[ {\sqrt {1 + \frac{{9\pi \sigma _{el} }}{{4k^2 \sigma _{tot}^2 }}} + 1} \right] - \frac{1}{{4k^2 }}(k = impulso del centro di massa).$$

 L'esponente A si riferisce al contributo della parte assorbente. Si ottengono restrizioni di unitarietà sull'ampiezza dell'elicità-flip

$$cf_{ + - }^A (t)/\sqrt { - t} |_{t = 0} $$

 in termini diσtot,σel, ebA(S).РезюмеМы обобщаем гранипу МкДовелла-Мартина для параметра наклонаbA для бесспинового случая на случай упругого рассеяния спина 0 на спине 1/2 с сохранением четности. Мы приводим онтимальный ответ для всех энергий, а также более простую гранипу гдеk—импульс в системе центра масс. Здесь индекс Ν относится к абсорбционному вкладу. Мы также получаем ограничения на амплитуду с изменением спиральности

$$cf_{ + - }^A (t)/\sqrt { - t} |_{t = 0} $$

 в терминахσполн,σупр иbA(S).
120083760
Effect of N/Z in pre-scission neutron multiplicity for 16,18O+194,198Pt systems
This paper report the summary of the experimental results of pre-scission neutron multiplicities from four compound nuclei, namely 210,212,214,216 Rn, and statistical model analysis of the corresponding data. The compound nuclei 210,212,214,216 Rn having N/Z values as 1.441, 1.465, 1.488, 1.511 respectively are populated through the 16,18 O+ 194,198 Pt reactions at excitation energies of 50, 61, 71.7 and 79 MeV. The measured neutron multiplicities are further analyzed with the statistical model of nuclear decay where fission hindrance due to nuclear dissipation is considered. The N/Z dependence of the dissipation strength at lowest excitation energy of the compound nuclei suggests shell closure effects. However, such effects are not observed at higher excitations where the variation of the dissipation strength with N/Z does not show any specific trend. The variation of N/Z in fission time scale is also shown.
123620633
Time-dependent Aharonov-Bohm Hamiltonian and admissibility criteria of quantum wave functions
SummarySelf-adjointness of the time-independent Aharonov-Bohm Hamiltonian is shown to allow a continuous family of different dynamics including those following from Pauli's criterion of rotational invariance, Aharonov-Bohm criterion of single valuedness and a version of Pauli's criterion appropriate to cylindrical symmetry suggested by Henneberger. A time-dependent fluxF(t) linking the Aharonov-Bohm solenoid leads to the time-dependent AB Hamiltonian. Explicit solutions in cases with and without inaccessible regions for the charged particle rule out applicability of both versions of the Pauli criterion. The solutions contain one time-independent parameter α, integer values of which correspond to single-valued wave functions. Any real (integer or noninteger) value of α is allowed. Charge and current densities depend on α andF(t) only through the combination α−eF(t)/2π and lead to the conclusion that physical effects of changing the flux during an experiment can be understood as local effects of the electric field inevitably associated with changing magnetic flux.RiassuntoSi mostra che la qualità di essere autoaggiunta dell'hamiltoniana indipendente dal tempo di Aharonov-Bohm permette una famiglia continua di dinamiche differenti che comprendono quelle che seguono dal criterio di Pauli dell'invarianza rotazionale, dal criterio di Aharonov-Bohm del singolo valore e da una versione del criterio di Pauli appropriata alla simmetria cilindrica suggerita da Henneberger. Un flussoF(t) dipendente del tempo che lega il solenoide di Aharonov-Bohm porta all'hamiltoniana AB dipendente dal tempo. Soluzioni esplicite nei casi con e senza regioni inaccessibili per la particella carica escludono l'applicabilità di entrambe le versioni del criterio di Pauli. Le soluzioni contengono un parametro indipendente del tempo α, i valori interi del quale corrispondono a funzioni d'onda a valore singolo. Si ammette qualunque valore reale di α (intero o non intero). La densità di carica e di corrente dipendono da α eF(t) solo attraverso la combinazione α−eF(t)/2π e portano alla conclusione che effetti fisici di cambiare il flusso durante un'esperimento possono essere considerati come effetti locali del campo elettrico inevitabilmente associato con il cambiamento del flusso magnetico.РезюмеПоказывается, что самосопряженность зависящего от времени Гамильтониана Аронова-Бома допускает непрерывное семейство различных динамик, включая динамики, которые вытекают из критерия Паули для ротационной инвариантности, критерия Аронова-Бома для однозначности и варианта критерия Паули, соответствующего цилиндрической симметрии, предложенной Хеннебергером. Зависящий от времени потокF(t), сваязывающий соленоид Аронова-Бома, приводит к зависящему от времени Гамильтониану Аронова-Бома. Точные решения в случае наличия и в случае отсутствия недоступных областей для заряженных частиц исключают возможность применения обоих вариантов критерия Паули. Решения содержат один зависящий от времени параметр α, целые значения которого соответствуют однозначным волновым функциям. Допускается любое вещественное (целое или не целое) значение параметра α. Плотности заряда и тока зависят от α иF(t) только через комбинацию α−eF(t)/2π. Этот результат приводит к выводу, что физические эффекты изменения потока во время эксперимента могут бытя интерпретированы, как локальные эффекты электрического поля, неизбежно связанные с изменяющимся магнитным потоком.