118019702
Search for resonance structures in inclusive charged pion spectra from p̄p annihilation at rest
The charged pion momentum spectra from pp annihilation at rest have been measured with high statistics. A search for structures finds four narrow lines which are identified with the absorption and decay processes of kaons stopping in the target. Limits of 1‐6×10−4/p (90% C.L.) are placed on the yield of a narrow state in the mass range 1000–1660 MeV.
116924174
Search for new strange resonances in inclusive charged kaon spectra from p̄p annihilation at rest
Charged spectra from pp annihilations at rest have been measured using the PS183 spectrometer at LEAR. From these data, charged kaon spectra are produced using time‐of‐flight separation. The spectra show structures corresponding to annihilation into the K±K−+ and K*±K−+ channels. A search for structures indicating other resonances is discussed.
116328057
The KTeV Pure CsI Calorimeter
KTeV is currently building a state-of-the-art pure CsI electromagnetic calorimeter with a sophisticated digital readout. The CsI array is expected to have better than 1% resolution over a dynamic range of 2--64 GeV. The design of the CsI array is driven by the difficult physics goal of attempting to measure the CP violation parameter Re({epsilon}{prime}/{epsilon}) to 1 part in 10000 in a high-rate neutral beam environment. The physics requirements and their impact on the final design will be discussed.
39950378
Measurement of the gamma gamma partial width of the chi 2 charmonium resonance.
The E760 Collaboration has studied the reaction [ital [bar p]p][r arrow][chi][sub 2][r arrow][gamma][gamma] using a hydrogen gas jet target in the Fermilab antiproton acumulator ring. The following values are obtained for the branching ratio and partial width to two photons; [ital B]([chi][sub 2][r arrow][gamma][gamma])=(1.60[plus minus]0.45)[times]10[sup [minus]4] and [Gamma]([chi][sub 2][r arrow][gamma][gamma])=321[plus minus]95 eV.
126084521
Measurements of the widths of charmonium states at the Fermilab anti-p accumulator ring
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
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.
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 $\cC$.
41160767
Chiral dynamics in QCD at finite chemical potential
We present the renormalized Taylor expansion of the chiral condensate with chemical potential. The relation with the Taylor coefficients of meson susceptibilities and the quark mass dependence of the quark number susceptibilities are obtained through chiral Ward identities and Maxwell relations. The continuum limit is obtained in quenched and two flavor QCD. In N{sub f}=2 QCD, the quadratic response coefficients of the chiral condensate to chemical potential indicate that pion fluctuations decrease at finite chemical potential toward the critical end point. We discuss how these observables can be used to test other features of the QCD phase diagram.
11476051
Observing Correlated Production of Defects and Antidefects in Liquid Crystals
We present observations of strength one defects and antidefects formed in isotropic-nematic phase transition in a thin layer of nematic liquid crystals, using a cross-polarizer setup. We measure the widths of the distributions of {\it net} winding number in small regions, and determine the exponent characterizing the correlation between defects and antidefects to be 0.26$\pm$0.11, in very good agreement with the value 1/4 predicted by the Kibble mechanism for defect production. We also describe a novel technique to determine the director distribution in observations of defect networks.
119295507
Heavy lepton pair production in nucleus–nucleus collisions at LHC energy – a case study
Abstract We present a study of τ + τ − lepton pair production in Pb + Pb collisions at s NN = 5.5 TeV . The larger τ ± mass (∼1.77 GeV) compared to e ± and μ ± leads to considerably small hadronic contribution to the τ + τ − pair invariant mass ( M ) distribution relative to the production from thermal partonic sources. The quark–anti-quark annihilation processes via intermediary virtual photon, Z and Higgs bosons have been considered for the production of τ + τ − . We observe that the contribution from Drell–Yan process dominates over thermal yield for τ + τ − pair mass from 4 to 20 GeV at the LHC energy. We also present the ratio of τ lepton pair yields for nucleus–nucleus collisions relative to yields from p + p collisions scaled by number of binary collisions at LHC energies as a function τ pair mass. The ratio is found to be significantly above unity for the mass range 4 to 6 GeV. This indicates the possibility of detecting τ + τ − pair from quark–gluon plasma (QGP) in the mass window 4 ⩽ M (GeV) ⩽ 6 .