Determination of the strong-coupling constant from the Z-boson transverse-momentum distribution
S. Camarda, Giancarlo Ferrera, M. Schott
Abstract
Abstract The strong-coupling constant is determined from the low-momentum region of the transverse-momentum distribution of Z bosons produced through the Drell–Yan process, using predictions at third order in perturbative QCD. The analysis employs a measurement performed in proton-antiproton collisions at a centre-of-mass energy of $$\sqrt{s} = 1.96$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> <mml:mo>=</mml:mo> <mml:mn>1.96</mml:mn> </mml:mrow> </mml:math> TeV with the CDF experiment. The determined value of the strong coupling at the reference scale corresponding to the Z -boson mass is $$\alpha _S(m_Z)= 0.1191^{+0.0013}_{-0.0016}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>α</mml:mi> <mml:mi>S</mml:mi> </mml:msub> <mml:mrow> <mml:mo>(</mml:mo> <mml:msub> <mml:mi>m</mml:mi> <mml:mi>Z</mml:mi> </mml:msub> <mml:mo>)</mml:mo> </mml:mrow> <mml:mo>=</mml:mo> <mml:mn>0</mml:mn> <mml:mo>.</mml:mo> <mml:msubsup> <mml:mn>1191</mml:mn> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>0.0016</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.0013</mml:mn> </mml:mrow> </mml:msubsup> </mml:mrow> </mml:math> .