ترغب بنشر مسار تعليمي؟ اضغط هنا

88 - Oleg Brandt 2015
In this article, I review recent measurements of the production of the top quark in $pbar p$ collisions at a centre-of-mass energy of $sqrt s=1.96$~TeV in Run II of the Fermilab Tevatron Collider, recorded by the CDF and D0 Collaborations. I will pre sent the Tevatron combination of measurements of the $tbar t$ production cross section and its differential measurement, the first evidence for and observation of the production of single top quarks in the $s$-channel, as well the final Tevatron combination of the production of single top quarks the $s$- and $t$-channels. Furthermore, I will review the measurements of the forward-backward asymmetry in $tbar t$ events, which can be experimentally uniquely accessed in the $CP$-invariant $pbar p$ initial state at the Tevatron, and conclude with the measurements of this asymmetry in the $bbar b$ system.
171 - Manfredi Ronzani 2014
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 tra nsverse 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.
116 - Pavol Bartos 2014
In this report, we summarize the latest results of the top-quark pair production asymmetry and present the new result of bottom-quark pair production asymmetry. By looking at the results obtained by the CDF experiment, one can see a discrepancy in bo th $tbar{t}$ inclusive and lepton-based measurements. The D0 results of the $tbar{t}$ production asymmetry are compatible with the standard-model predictions as well as with the CDF results. The CDF measurement of $bbar{b}$ production asymmetry presents consistency with both zero and with the standard-model predictions.
109 - R. Schwienhorst 2014
The production of single-top quarks occurs via the weak interaction at the Fermilab Tevatron proton-antiproton collider. Single top quark 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. Multivariate classifiers separate the s-channel and t-channel single-top signals from the large backgrounds. The combination of CDF and D0 results leads to the first observation of the s-channel mode of single top quark production. The t-channel and single top combined cross sections have also been measured.
The top quark is the heaviest known elementary particle, with a mass about 40 times larger than the mass of its isospin partner, the bottom quark. It decays almost 100% of the time to a $W$ boson and a bottom quark. Using top-antitop pairs at the Tev atron proton-antiproton collider, the CDF and {dzero} collaborations have measured the top quarks mass in different final states for integrated luminosities of up to 5.8 fb$^{-1}$. This paper reports on a combination of these measurements that results in a more precise value of the mass than any individual decay channel can provide. It describes the treatment of the systematic uncertainties and their correlations. The mass value determined is $173.18 pm 0.56 thinspace ({rm stat}) pm 0.75 thinspace ({rm syst})$ GeV or $173.18 pm 0.94$ GeV, which has a precision of $pm 0.54%$, making this the most precise determination of the top quark mass.
239 - Mirco Dorigo 2012
The CDF and D0 experiments at the Tevatron ppbar collider have pioneered and established the role of flavor physics in hadron collisions. A broad program is now at its full maturity. We report on three new results sensitive to physics beyond the stan dard model, obtained using the whole CDF dataset: a measurement of the difference of CP asymmetries in $K^+K^-$ and $pi^+pi^-$ decays of $D^0$ mesons, new bounds on the $B^0_s$ mixing phase and on the decay width difference of $B^0_s$ mass-eigenstates, and an update of the summer 2011 search for $B^0_(s)$ mesons decaying into pairs of muons. Finally, the D0 confirmation of the observation of a new hadron, the $chi_b(3P)$ state, is briefly mentioned.
We report the combination of recent measurements of the helicity of the W boson from top quark decay by the CDF and D0 collaborations, based on data samples corresponding to integrated luminosities of 2.7 - 5.4 fb^-1 of ppbar collisions collected dur ing Run II of the Fermilab Tevatron Collider. Combining measurements that simultaneously determine the fractions of W bosons with longitudinal (f0) and right-handed (f+) helicities, we find f0 = 0.722 pm 0.081 [pm 0.062 (stat.) pm 0.052 (syst.)] and f+ = -0.033 pm 0.046 [pm 0.034 (stat.) pm 0.031 (syst.)]. Combining measurements where one of the helicity fractions is fixed to the value expected in the standard model, we find f0 = 0.682 pm 0.057 [pm 0.035 (stat.) pm 0.046 (syst.)] and f+ = -0.015pm0.035 [pm 0.018 (stat.) pm 0.030 (syst.)]. The results are consistent with standard model expectations.
The CDF and DO experiments at the Tevatron $pbar{p}$ collider established that extensive and detailed exploration of the $b$--quark dynamics is possible in hadron collisions, with results competitive and supplementary to those from $e^+e^-$ colliders . This provides a rich, and highly rewarding program that is currently reaching full maturity. I report a few recent world-leading results on rare decays, CP-violation in $B^0_s$ mixing, $bto s$ penguin decays, and charm physics.
123 - Mirco Dorigo 2010
The Tevatron provides 1.96 TeV ppbar collisions and allows for collection of rich b-hadron samples to the two experiments CDF and D0. The study of heavy flavor properties represents a fruitful opportunity to investigate the flavor sector of the Stand ard Model (SM) and to look for hints of New Physics (NP). Here we report the first measurement of polarization amplitudes in B^0_s charmless decays, world leading results on b-hadron lifetimes, and measurements of several other properties of b-hadrons.
Processes involving flavor changing neutral currents (FCNC) provide excellent signatures with which to search for evidence of new physics. They have very small branching fractions in the Standard Model since they are highly suppressed by Glashow-Ilio poulos-Maiani (GIM) mechanism. They occur only through higher order diagrams, and new particles contributions can provide a significant enhancements, which would be an uniquevocal signs of physics beyond the Standard Model. In this paper we present the most recent measurements on FCNC processes performed by CDF and D0 Collaborations, while last section is devote to the charm physics at CDF.
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا