First observation of top quark production in the forward region.

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Patel,K Kurek,F Blanc,S Lohn,E Bowen,D Wiedner,R Santacesaria,C Farinelli,O Schneider,U Egede,N Rauschmayr,S Ogilvy,J Serrano,M Szczekowski,G Veneziano,A Sciubba,D Galli,C Potterat,A Zhelezov,C Baesso,G Wilkinson,G Penso,L Giubega,P Naik,I Nasteva,G Raven,C Wallace,M Karacson,F Teubert,M Tobin,Y Shcheglov,E Polycarpo,A Lai,W Bonivento,R Le Gac,I Longstaff,D Brett,L Del Buono,S Gallorini,C Langenbruch,B Pietrzyk,J Wimberley,M Van Beuzekom,C Linn,R Graciani Diaz,K Carvalho Akiba,R Silva Coutinho,A Mazurov,B Muster,D Lambert,W Kanso,P Marino,C Lazzeroni,T Head,C Göbel,N Neufeld,P Spradlin,S Karodia,F Ferreira Rodrigues,E Ben-Haim,C Vázquez Sierra,L Zhong,M Coombes,A Satta,S Klaver,A Puig Navarro,R Calabrese,M Deckenhoff,W Sutcliffe,M Grabalosa Gándara,C Matteuzzi,M Liles,M Zangoli,A Hicheur,M Pappagallo,S Topp-Joergensen,S Wright,A Jaeger,T Pilař,P Collins,A Vorobyev,I Raniuk,V Tisserand,M Baalouch,E Gushchin,O Yushchenko,M Mussini,R Nandakumar,L Shekhtman,M Calvo Gomez,S Gregson,M Rama,A 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doi:10.1103/physrevlett.115.112001

Abstract

Top quark production in the forward region in proton-proton collisions is observed for the first time. The W+b final state with W→μν is reconstructed using muons with a transverse momentum, p_{T}, larger than 25GeV in the pseudorapidity range 2.0<η<4.5. The b jets are required to have 50<p_{T}<100 GeV and 2.2<η<4.2, while the transverse component of the sum of the muon and b-jet momenta must satisfy p_{T}>20 GeV. The results are based on data corresponding to integrated luminosities of 1.0 and 2.0 fb^{-1} collected at center-of-mass energies of 7 and 8TeV by LHCb. The inclusive top quark production cross sections in the fiducial region are σ(top)[7 TeV]=239±53(stat)±33(syst)±24(theory) fb,σ(top)[8 TeV]=289±43(stat)±40(syst)±29(theory) fb.These results, along with the observed differential yields and charge asymmetries, are in agreement with next-to-leading order standard model predictions.

Highlights

Top quark production in the forward region in proton-proton collisions is observed for the first time
In the standard model (SM), four processes make significant contributions to top quark production: tt pair production, single-top production via processes mediated by a W boson in the t channel or in the s channel, and single top produced in association with a W boson
The SM predicts that about 75% of t → Wb decays in the forward region are due to tt pair production

Summary

Introduction

Top quark production in the forward region in proton-proton collisions is observed for the first time. The two-dimensional distribution of the BDT responses observed in data is fitted to obtain the SV-tagged b, c, and light-parton jet yields.

Results

Conclusion