A search for the pair production of supersymmetric partner of the top quark in scenario with R-parity violation is presented. The quantum number called R-parity distinguishes particles in standard model from supersymmetric particles. A scalar top quark (stop) is assumed to decay only via R{sub p}-violating supersymmetric coupling into tau lepton and b-quark. To collect events with multiple taus, a new special tau trigger (the lepton plus track trigger) is installed in Run II experiment of the Collider Detector at Fermilab (CDF). The goal of the lepton plus track trigger is to collect generic dilepton ({ell}{ell}, {ell}{tau}, {tau}{tau}) events with lower p{sub T} threshold (8 GeV/c) and without prescale even at high luminosity. The Z {yields} {tau}{tau} event, where one {tau}-lepton decays leptonically and the other hadronically, is a good benchmark to calibrate the lepton plus track trigger and {tau} identification. The data sample of 72 pb{sup -1}, collected using the electron plus track trigger, contains clear a {tau} signal from Z {yields} {tau}{tau} events. The data used in stop search correspond to 200 pb{sup -1}. The lower stop mass bound of 134 GeV/c{sup 2} at a 95% confidence level is obtained. This limit is also directly applicable to the case of the third generation scalar leptoquark (LQ{sub 3}) assuming a 100% branching for the LQ{sub 3} {yields} {tau}b decay mode.

Abstract Not Provided.

A search for the pair production of supersymmetric partner of the top quark in scenario with R-parity violation is presented. The quantum number called R-parity distinguishes particles in standard model from supersymmetric particles. A scalar top quark (stop) is assumed to decay only via Rp-violating supersymmetric coupling into tau lepton and b-quark. To collect events with multiple taus, a new special tau trigger (the lepton plus track trigger) is installed in Run II experiment of the Collider Detector at Fermilab (CDF). The goal of the lepton plus track trigger is to collect generic dilepton (ll, l?, ??) events with lower pT threshold (8 GeV/c) and without prescale even at high luminosity. The Z → ?? event, where one ?-lepton decays leptonically and the other hadronically, is a good benchmark to calibrate the lepton plus track trigger and ? identification. The data sample of 72 pb-1, collected using the electron plus track trigger, contains clear a ? signal from Z → ?? events. The data used in stop search correspond to 200 pb-1. The lower stop mass bound of 134 GeV/c2 at a 95% confidence level is obtained. This limit is also directly applicable to the case of the third generation scalar leptoquark (LQ3) assuming a 100% branching for the LQ3 → ?b decay mode.

We present the results of a search for pair production of scalar top quarks ({tilde t}1) in an R-parity violating supersymmetric scenario using 322 pb−1 of p{bar p} collisions at √s = 1.96 TeV collected by the upgraded Collider Detector at Fermilab. We assume each {tilde t}1 decays into a? lepton and a b quark with a branching ratio?, and that the final state contains either an electron or a muon from a leptonic? decay, a hadronically decaying? lepton, and two or more jets. Two candidate events pass our final selection criteria, consistent with the expectation from standard model processes. We present upper limits on the cross section times branching ratio squared?({tilde t}1{bar {tilde t}}1) x?2 as a function of the stop mass m({tilde t}1). Assuming? = 1, we set a 95% confidence level limit m({tilde t}1)> 153 GeV=c2 obtained using a next-to-leading order cross section. These limits are also fully applicable to the case of a pair produced third generation scalar leptoquark decaying into a? lepton and a b quark.

I present the results of a search for pair production of scalar top quarks ($ ilde{t}$1) in an R-parity violating supersymmetric scenario using 322 pb-1 of p{bar p} collisions at √s = 1.96 TeV collected by the upgraded Collider Detector at Fermilab. I assume each $ ilde{t}$1 decays into a ? lepton and a b quark, with branching ratio ?, and search for final states containing either an electron or a muon from a leptonic ? decay, a hadronically decaying ? lepton, and two or more jets. Two candidate events pass my final selection criteria, consistent with the expectation from standard model processes. I present upper limits on the cross section times branching ratio squared ?($ ilde{t}$1$ ilde{t}$1) x ?2 as a function of the stop mass m($ ilde{t}$1). Assuming ? = 1, I set a 95% confidence level limit m($ ilde{t}$1) > 153 GeV=c2. These limits are also fully applicable to the case of a pair produced third generation scalar leptoquark that decays into a ? lepton and a b quark.

I present the results of a search for pair production of scalar top quarks (t̃1) in an R-parity violating supersymmetric scenario using 322 pb−1 of pp collisions at [square root]s = 1.96 TeV collected by the upgraded Collider Detector at Fermilab. I assume each t̃1 decays into a [tau] lepton and a [beta] quark, with branching ratio [beta], and search for nal states containing either an electron or a muon from a leptonic [tau] decay, a hadronically decaying [tau] lepton, and two or more jets. Two candidate events pass my nal selection criteria, consistent with the expectation from standard model processes. I present upper limits on the cross section times branching ratio squared [sigma](t̃1t̃1) X [beta]2 as a function of the stop mass (mt̃1). Assuming [beta]= 1, I set a 95% condence level limit m(t̃1)> 153 GeV=c2. These limits are also fully applicable to the case of a pair produced third generation scalar leptoquark that decays into a [tau] lepton and a [beta] quark.