Search for stopped gluinos from p(p)over-bar collisions at root s=1.96 TeV

Long-lived, heavy particles are predicted in a number of models beyond the standard model of particle physics. We present the first direct search for such particles' decays, occurring up to 100 h after their production and not synchronized with an accelerator bunch crossing. We apply the analysis to the gluino (g), predicted in split supersymmetry, which after hadronization can become charged and lose enough momentum through ionization to come to rest in dense particle detectors. Approximately 410 pb(-1) of p (p) over bar collisions at root s = 1.96 TeV collected with the D0 detector during Run II of the Fermilab Tevatron collider are analyzed in search of such stopped gluinos decaying into a gluon and a neutralino ((chi) over tilde (0)(1)). Limits are placed on the (gluino cross section) x (probability to stop) x [BR((g) over tilde -> g (chi) over tilde (0)(1))] as a function of the gluino and (chi) over tilde (0)(1) masses, for gluino lifetimes from 30 mu s-100 h.

Vacuum polarization effects in hyperon-rich dense matter - a nonperturbative treatment

We derive the equation of state (EOS) for electrically charged neutral dense matter using the quantum hadrodynamics (QHD) model. This is carried out in a non-perturbative manner including quantum corrections for baryons through a realignment of vacuum with baryon-antibaryon condensates. This yields the results of relativistic Hartree approximation of summing over baryonic tadpole diagrams. The quantum corrections from the scalar meson is also taken into account in a similar way. This leads to a softening of the EOS for the hyperonic matter. The formalism also allows Lis to make a self-consistent calculation of the in-medium sigma meson mass. The effects of such quantum corrections on the composition of charged neutral dense matter is considered. The effect of the resulting EOS on the structure of neutron stars is also studied.

Resonant production of scalar diquarks at the next generation electron-positron colliders

We investigate the potential of TESLA and JLC/NLC electron-positron linear collider designs to observe diquarks produced resonantly in processes involving hard photons.

Measuring Higgs coupling to tau-leptons at future e(+)e(-) colliders

We perform a complete simulation of the process e(+)e(-) --> tau(+)tau(-)nu(ν) over bar where nu can be an electron, muon or tau neutrino, in the context of a general Higgs coupling to tau-leptons. We analyse various kinematical distributions and obtain the sensitivity regions in the parameter space that can be explored at a future e(+)e(-) collider. In particular, inclusion of W boson fusion enhances the sensitivity significantly.

Strangeness data with heavy projectiles from a hydrodynamical point of view

We compare the results obtained by using the continuous emission model with data from Ph-Ph collisions. We determine the initial conditions necessary to reproduce the strange particle ratios (experiment WA97) and with the obtained results, we study the dependence on particle mass of the inverse slope parameter T. Some particle spectra are also shown.

Constraints on four-fermion contact interactions from precise electroweak measurements

We establish constraints on a general four-fermion contact interaction from precise measurements of electroweak parameters. We compute the one-loop contribution for the leptonic Z width, anomalous magnetic, weak-magnetic, electric and weak dipole moments of leptons in order to extract bounds on the energy scale of these effective interactions.

Measurement of Bose-Einstein correlations in pp collisions at the LHC with CMS

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Measurement of the differential dijet production cross section in proton-proton collisions at root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Measurement of the ratio of the 3-jet to 2-jet cross sections in pp collisions at root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Search for squeezed-pair correlations at RHIC

Squeezed correlations of particle-antiparticle pairs, also called back-to-back correlations (BBC), are predicted to appear if the hadron masses are modified in the hot and dense hadronic medium formed in high energy nucleus nucleus collisions. Although well established theoretically, the squeezed-particle correlations have not yet been searched for experimentally in high energy hadronic or heavy ion collisions, clearly requiring optimized forms to experimentally search for this effect. Within a non-relativistic treatment developed earlier we show that one promising way to search for the BBC signal is to look into the squeezed correlation function of pairs of phi's at RHIC energies, plotted in terms of the average momentum of the pair, K(12) = 1/2 (k(1) + k(2)). This variable's modulus, 2 vertical bar K(12)vertical bar, is the non-relativistic limit of the variable Q(bbc), introduced herewith. Some squeezing effects on the HBT correlation function are also discussed.

Squeezed correlations of strange particles-antiparticles

Squeezed correlations of hadron-antihadron pairs are predicted to appear if their masses are modified in the hot and dense medium formed in high-energy heavy ion collisions. If discovered experimentally, they would be an unequivocal evidence of in-medium mass shift found by means of hadronic probes. We discuss a method proposed to search for this novel type of correlation, illustrating it by means of D(s)-mesons with in-medium shifted masses. These particles are expected to be more easily detected and identified in future upgrades at RHIC.

Search for a heavy gauge boson W ' in the final state with an electron and large missing transverse energy in pp collisions at root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A New Boson with a Mass of 125 GeV Observed with the CMS Experiment at the Large Hadron Collider

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Observing Higgs dark matter at the CERN LHC

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)