119340706
Susceptibilities and speed of sound from PNJL model
We present the Taylor expansion coefficients of the pressure in quark number chemical potential $\mu_0=\mu_B / 3=\mu_u=\mu_d$, for the strongly interacting matter as described by the PNJL model for two light degenerate flavours of quarks u and d. The expansion has been done upto eighth order in $\mu_0$, and the results are consistent with recent estimates from Lattice. We have further obtained the specific heat $C_V$, squared speed of sound $v_s^2$ and the conformal measure $\cC$.
122350530
Models for Strong Interaction Physics
Abstract We review the developments in various models describing strong interaction physics. The models provide an intuitive way of understanding the complex phenomenon associated with strong interactions. Models also help us to delve into regions of couplings and other thermodynamic conditions of interest that are still out of reach of the first principle method - quantum chromodynamics. At the same to ascertain the merits of the models they should be contrasted to the results obtained from quantum chromodynamics at least in its region of validity, and to the available experimental data. Here we shall discuss about our progress in that direction.
17726542
Formation and collapse of false vacuum bubbles in relativistic heavy-ion collisions
Abstract It is possible that under certain situations, in a relativistic heavy-ion collision, partons may expand out forming a shell like structure. We analyze the process of hadronization in such a picture for the case when the quark–hadron transition is of first order, and argue that the inside region of such a shell must correspond to a supercooled (to T=0 ) deconfined vacuum. Hadrons from that region escape out, leaving a bubble of pure deconfined vacuum with large vacuum energy. This bubble undergoes relativistic collapse, with highly Lorentz contracted bubble walls, and may concentrate the entire energy into extremely small regions. Eventually different portions of bubble wall collide, with the energy being released in the form of particle production. Thermalization of this system can lead to very high temperatures. With a reasonably conservative set of parameters, at LHC, the temperature of the hot spot can reach as high as 3 GeV, and well above it with more optimistic parameters. Such a hot spot can leave signals like large P T partons, dileptons, and enhanced production of heavy quarks. We also briefly discuss a speculative possibility where the electroweak symmetry may get restored in the highly dense region resulting from the decay of the bubble wall via the phenomenon of non-thermal symmetry restoration (which is usually employed in models of pre-heating after inflation). If that could happen then the possibility may arise of observing sphaleron induced baryon number violation in relativistic heavy-ion collisions.
119158093
The consequences of SU (3) colorsingletness, Polyakov Loop and Z (3) symmetry on a quark–gluon gas
Based on quantum statistical mechanics we show that the SU(3) color singlet ensemble of a quark-gluon gas exhibits a Z(3) symmetry through the normaized character in fundamental representation and also becomes equivalent, within a stationary point approximation, to the ensemble given by Polyakov Loop. Also Polyakov Loop gauge potential is obtained by considering spatial gluons along with the invariant Haar measure at each space point. The probability of the normalized character in SU(3) vis-a-vis Polyakov Loop is found to be maximum at a particular value exhibiting a strong color correlation. This clearly indicates a transition from a color correlated to uncorrelated phase or vise-versa. When quarks are included to the gauge fields, a metastable state appears in the temperature range 145 T(MeV) 170 due to the explicit Z(3) symmetry breaking in the quark-gluon system. Beyond T 170 MeV the metastable state disappears and stable domains appear. At low temperature a dynamical recombination of ionized Z(3) color charges to a color singlet Z(3) confined phase is evident along with a confining background that originates due to circulation of two virtual spatial gluons but with conjugate Z(3) phases in a closed loop. We also discuss other possible consequences of the center domains in the color deconfined phase at high temperature.
118413103
Entropy scaling and thermalization in hadron-hadron collisions at LHC
The recent LHC data have once more brought the issue of the formation of thermalized state of matter in hadron-hadron collisions into the forefront. In this letter, we have shown that the scaling of the information entropy of the chaotically produced particles is valid up to recently available data from p+p collisions at $\sqrt{s}$ = 2.36 TeV obtained by ALICE experiment. We predict that at the highest energies projected for LHC, almost all the particles will be produced chaotically, indicating that a collective behavior should be observed in hadronic collisions, as indicated by one of present authors quite some time ago.
119152850
Wakes in a collisional quark-gluon plasma
Wakes created by a parton moving through a static and infinitely extended quark?gluon plasma are considered. In contrast to former investigations, collisions within the quark?gluon plasma are taken into account using a transport theoretical approach (Boltzmann equation) with a Bhatnagar?Gross?Krook collision term. Within this model, it is shown that the wake structure changes significantly compared to the collisionless case.
123588442
A search for structure in charged meson spectra from proton-antiproton annihilations at rest
The charged meson momentum spectra from pp annihilation at rest have been measured with high statistics. A search is made for structures between 150 and 300 MeV/c which indicate narrow baryonium states. We find four narrow lines which are identified with the absorption and decay processes of kaons stopping in the target. No other narrow structures are seen, giving limits of 2−6×10−4 p (90% CL) for the yield of a narrow state in the mass range 1510–1660 MeV.
125360362
A program to measure the direct CP violating decay K(L) --> pi0 nu anti-nu and other rare decays at Fermilab using the main injector
123205836
The E760 lead-glass central calorimeter: design and initial test results
The central calorimeter in Fermilab experiment E760++ has been designed to measure the topology and energies of electrons and photons in the decay of charmonium formed in pp annihilation. The calorimeter is composed of 1280 lead-glass Cherenkov counters read out with photomultiplier tubes. This paper discusses design criteria for the calorimeter and describes how these criteria were met. Data from tests in low energy (10–84 MeV) and medium energy (1–4 GeV) beams are presented showing a spatial resolution of 9 mm, an energy resolution of (3.0 ± 0.3)%√E[GeV] + (1.5 ± 0.5)%, and an effective energy threshold below 10 MeV.
118620496
Observation of narrow lines in the spectra of charged mesons produced in antiproton-proton annihilation at rest
123723655
The NOvA experiment
The NOvA Project will construct a 15 kt Far Detector 835 km from Fermilab at Ash River Minnesota, a 220 ton Near Detector on the Fermilab site and upgrade the existing NuMI beamline from 400 kW to 700 kW. The detector technology is liquid scintillator captured in reflective rigid PVC cells. The light is captured using WLS fibre and routed to avalanche photo diodes. NO?A is designed to observe the appearance of electron neutrinos, determine the value of sin{sup 2}(2{theta}{sub 13}) and begin the study of CP violation in the neutrino sector. NO?A is the only currently approved experiment with the ability to determine the neutrino mass ordering. The NOvA physics program and projected sensitivities are described in this report.