Manfredi Ronzani

This paper reports the most recent measurements of the cross sections for the two main production modes of single top quarks in p p collisions at a center-of-mass energy of 1.96 TeV in the Run II data collected with the CDF and D0 detector at the Fermilab Tevatron Collider.For this measurement the full data set corresponding to an integrated luminosity of up to 9.7 fb -1 per experiment is used.We report the first observation of single top quark production in the s-channel with a significance of 6.3 standard deviations.We also present a simultaneous measurement of the production cross section of tand s + t-channels.Using these measurements we set a lower limit on the CKM matrix element |V tb | > 0.92 at 95% C.L., assuming m t = 172.5 GeV.Moreover, we present a search for charged massive resonances decaying to top (t) and bottom (b) quarks performed at CDF in the same data set.No significant excess above the standard model (SM) background prediction is observed and constraints on the W → tb mass and couplings in the 300 to 900 GeV/c 2 range are set.

This proceeding summarises results on inclusive searches for squarks and gluinos in final state containing jets, missing transverse momentum and no leptons (0L). The first search presented uses the full dataset recorded in 2012 by the ATLAS experiment in √ s = 8 TeV centre-of-mass energy pp collisions at the LHC, corresponding to a total luminosity of 20.3 fb−1. No significant excess above the Standard Model expectations is observed and several interpretations in the context of simplified phenomenological supersymmetric models are shown. Moreover, sensitivity studies for gluino pair production with a full simulation of the ATLAS detector at a centre-of-mass energy of 13 TeV are presented. In the end, the first Run2 data distributions in regions dominated by the W+jets, Z+jets and combined top events in the same final state are shown. Data are collected by the ATLAS experiment at √ s = 13 TeV in 2015, corresponding to an integrated luminosity of 78 pb−1.

This paper reports the most recent measurements of single top quark production performed by CDF and D0 collaborations in proton-antiproton collisions at Tevatron. Events are selected in the lepton+jets final state by CDF and D0 and in the missing transverse energy plus jets final state by CDF. The small single top signal in s-channel, t-channel and inclusive s+t channel is separated from the large background by using different multivariate techniques. We also present the most recent results on extraction of the CKM matrix element $$|V_{tb}|$$ from the single top quark cross section.

This paper reports the most recent measurements of single top quark production performed by CDF and D0 collaborations in proton-antiproton collisions at Tevatron. Events are selected in the lepton+jets final state by CDF and D0 and in the missing transverse energy plus jets final state by CDF. The small single top signal in s-channel, t-channel and inclusive s+t channel is separated from the large background by using different multivariate techniques. We also present the most recent results on extraction of the CKM matrix element $|V_{tb}|$ from the single top quark cross section.

The Top quark was observed at the Fermilab Tevatron by the CDF and D0 collaboration in 1995 via strong production of top quarks pairs at center-of-mass energy of $ \sqrt{s}=1.8 $ Tev, using 60 pb-1 of data [1]. Standard Model of elementary particles predicts top quark to be produced individually via electroweak interactions in three different channels (s, t and Wt). This is defined as ”single top” (from now on also ST). ST was observed by CDF collaboration in 2009 at center-of-mass energy of $ \sqrt{s}=1.96 $ Tev using 3.2 fb-1 of $ p\overline{p}\ $ collected data [2]. This thesis concerns the upgrade of this measurement using 7.5 fb-1 of data.

Missing transverse momentum (E missT ) is a useful way to signal particles not interacting with the detector such as those predicted by Beyond Standard Model theories.The ATLAS experiment at the LHC employs a missing transverse momentum trigger that uses calorimeter-based global energy sums, together with specifically developed pile-up mitigation techniques, to keep the selection efficiency high for events with non-interacting particles while minimizing the overall trigger rate.The high number of pile-up interactions was one of the major challenges faced during the Run 2 of the LHC and a continuous effort was needed to improve the pile-up rejection and to keep the trigger rate reasonable.This contribution presents the techniques used to improve the Run 2 missing transverse momentum trigger performance, describes the Run 2 performance and discusses an outlook for further improvements for Run 3 of the LHC.