On Testing Dependence between Time to Failure and Cause of Failure when Causes of Failure Are Missing

The hypothesis of independence between the failure time and the cause of failure is studied by using the conditional probabilities of failure due to a specific cause given that there is no failure up to certain fixed time. In practice, there are situations when the failure times are available for all units but the causes of failures might be missing for some units. We propose tests based on U-statistics to test for independence of the failure time and the cause of failure in the competing risks model when all the causes of failure cannot be observed. The asymptotic distribution is normal in each case. Simulation studies look at power comparisons for the proposed tests for two families of distributions. The one-sided and the two-sided tests based on Kendall type statistic perform exceedingly well in detecting departures from independence

Pairing in nuclear systems: from neutron stars to finite nuclei

We discuss several pairing-related phenomena in nuclear systems, ranging from superfluidity in neutron stars to the gradual breaking of pairs in finite nuclei. We focus on the links between many-body pairing as it evolves from the underlying nucleon-nucleon interaction and the eventual experimental and theoretical manifestations of superfluidity in infinite nuclear matter and of pairing in finite nuclei. We analyse the nature of pair correlations in nuclei and their potential impact on nuclear structure experiments. We also describe recent experimental evidence that points to a relation between pairing and phase transitions (or transformations) in finite nuclear systems. Finally, we discuss recent investigations of ground-state properties of random two-body interactions where pairing plays little role although the interactions yield interesting nuclear properties such as 0+ ground states in even-even nuclei.Comment: 74 pages, 33 figs, uses revtex4. Submitted to Reviews of Modern Physic

Study of direct CP violation in B+- ---> J/psi K+- (pi+-) file decays

The authors present a search for direct CP violation in B{sup {+-}} {yields} J/{psi}K{sup {+-}}{pi}{sup {+-}} decays. The event sample is selected from 2.8 fb{sup -1} of p{bar p} collisions recorded by D0 experiment in Run II of the Fermilab Tevatron Collider. The charge asymmetry A{sub CP}(B{sup +} {yields} J/{psi}K{sup +}) = +0.0075 {+-} 0.0061(stat.) {+-} 0.0027(syst.) is obtained using a sample of approximately 40 thousand B{sup {+-}} {yields} J/{psi}K{sup {+-}} decays. The achieved precision is of the same level as the expected deviation predicted by some extensions of the standard model. They also measured the charge asymmetry A{sub CP}(B{sup +} {yields} J/{psi}{pi}{sup +}) = -0.09 {+-} 0.08(stat.){+-}0.03(syst.)

Search for sneutrino particles in e + mu final states in p anti-p collisions at s**(1/2) = 1.96-TeV

We report a search for R-parity violating production and decay of sneutrino particles in the e{mu} final state with 1.04 {+-} 0.06 fb{sup -1} of data collected with the D0 detector at the Fermilab Tevatron Collider in 2002-2006. Good agreement between the data and the standard model prediction is observed. With no evidence for new physics, we set limits on the R-parity violating couplings {lambda}'{sub 311} and {lambda}{sub 312} as a function of sneutrino mass