A first measurement of the polarization of W bosons with large transverse momenta in pp collisions is presented. The measurement is based on 36 pb(-1) of data recorded at root s = 7 TeV by the CMS detector at the LHC. The left-handed, right-handed, and longitudinal polarization fractions (f(L), f(R), and f(0), respectively) of W bosons with transverse momenta larger than 50 GeV are determined by using decays to both electrons and muons. The muon final state yields the most precise measurement: (f(L) - f(R))(-) = 0.240 +/- 0.036(syst) +/- 0.031(syst) and f(0)(-) = 0.183 +/- 0.087(stat) +/- 0.123(syst) for negatively charged W bosons and (f(L) - f(R))(+) = 0.310 +/- 0.036(syst) +/- 0.017(syst) and f(0)(+) = 0.171 +/- 0.085(syst) +/- 0.099(syst) for positively charged W bosons. This establishes, for the first time, that W bosons produced in pp collisions with large transverse momenta are predominantly left-handed, as expected in the standard model. RI Stahl, Achim/E-8846-2011; Mertzimekis, Theodore/A-3287-2008; Hektor, Andi/G-1804-2011; Wulz, Claudia-Elisabeth/H-5657-2011; Chen, Jie/H-6210-2011; Bolton, Tim/A-7951-2012; Yang, Fan/B-2755-2012; Krammer, Manfred/A-6508-2010; Tinoco Mendes, Andre David/D-4314-2011; Petrushanko, Sergey/D-6880-2012; Lokhtin, Igor/D-7004-2012; Kodolova, Olga/D-7158-2012; Dudko, Lev/D-7127-2012; Perfilov, Maxim/E-1064-2012; Belyaev, Andrey/E-1540-2012; Katkov, Igor/E-2627-2012; Boos, Eduard/D-9748-2012; Snigirev, Alexander/D-8912-2012; Tomei, Thiago/E-7091-2012; Focardi, Ettore/E-7376-2012; Novaes, Sergio/D-3532-2012; Padula, Sandra /G-3560-2012; Flix, Josep/G-5414-2012; Fruhwirth, Rudolf/H-2529-2012; Azzi, Patrizia/H-5404-2012; Torassa, Ezio/I-1788-2012

Measurement of the Polarization of W Bosons with Large Transverse Momenta in W plus jets Events at the LHC

LIGABUE, FRANCO;ROLANDI, LUIGI;
2011

Abstract

A first measurement of the polarization of W bosons with large transverse momenta in pp collisions is presented. The measurement is based on 36 pb(-1) of data recorded at root s = 7 TeV by the CMS detector at the LHC. The left-handed, right-handed, and longitudinal polarization fractions (f(L), f(R), and f(0), respectively) of W bosons with transverse momenta larger than 50 GeV are determined by using decays to both electrons and muons. The muon final state yields the most precise measurement: (f(L) - f(R))(-) = 0.240 +/- 0.036(syst) +/- 0.031(syst) and f(0)(-) = 0.183 +/- 0.087(stat) +/- 0.123(syst) for negatively charged W bosons and (f(L) - f(R))(+) = 0.310 +/- 0.036(syst) +/- 0.017(syst) and f(0)(+) = 0.171 +/- 0.085(syst) +/- 0.099(syst) for positively charged W bosons. This establishes, for the first time, that W bosons produced in pp collisions with large transverse momenta are predominantly left-handed, as expected in the standard model. RI Stahl, Achim/E-8846-2011; Mertzimekis, Theodore/A-3287-2008; Hektor, Andi/G-1804-2011; Wulz, Claudia-Elisabeth/H-5657-2011; Chen, Jie/H-6210-2011; Bolton, Tim/A-7951-2012; Yang, Fan/B-2755-2012; Krammer, Manfred/A-6508-2010; Tinoco Mendes, Andre David/D-4314-2011; Petrushanko, Sergey/D-6880-2012; Lokhtin, Igor/D-7004-2012; Kodolova, Olga/D-7158-2012; Dudko, Lev/D-7127-2012; Perfilov, Maxim/E-1064-2012; Belyaev, Andrey/E-1540-2012; Katkov, Igor/E-2627-2012; Boos, Eduard/D-9748-2012; Snigirev, Alexander/D-8912-2012; Tomei, Thiago/E-7091-2012; Focardi, Ettore/E-7376-2012; Novaes, Sergio/D-3532-2012; Padula, Sandra /G-3560-2012; Flix, Josep/G-5414-2012; Fruhwirth, Rudolf/H-2529-2012; Azzi, Patrizia/H-5404-2012; Torassa, Ezio/I-1788-2012
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11384/2924
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