Inclusive low mass Drell-Yan production in the forward region at √s = 7 TeV

The conference note is available here (LHCb-CONF-2012-013).

More detailed information: ANA note 2012-029

Abstract

This note presents the measurement of the Drell-Yan cross-section in dimuon final states for muons within pseudorapidities of 2 to 4.5, in the mass range 5<Mμμ<120 GeV/c2. The muons are required to have a momentum larger than 10 GeV/c and a transverse momentum larger that 3 GeV/c. For masses above 40 GeV/c2 the transverse momentum needs to be larger than 15 GeV/c. The cross section is measured differentially, in mass, and in rapidity of the virtual photon (γ⋆) in two distinct mass regions. The analysis uses the full dataset collected by the LHCb experiment during 2010 with an integrated luminosity of 37 pb−1.

Figures

(Note, pdf versions are available under attachments).

Caption Figure
The dimuon invariant mass for the Z → μμ events. A Crystal Ball function for the signal and an exponential for the background are fitted. Fig01a.png
The dimuon invariant mass for the Υ samples. A Crystal Ball function for the signal and an exponential for the background are fitted Fig01b.png
The dimuon invariant mass for the J/ψ samples. A Crystal Ball function for the signal and an exponential for the background are fitted Fig01c.png
The dimuon invariant mass for the J/ψ K samples. A Crystal Ball function for the signal and an exponential for the background are fitted Fig01d.png
Misidentification probability for muons due to decay in flight as a function of the longitudinal momentum together with the fit for the misidentification probability. Fig02.png
Comparison of data and simulation of the distribution of the minimum isolation for muons from (left) Υ → μμ , (right) Z → μμ decays. Fig03.png
Comparison of data and simulation of the distribution of the minimum isolation for muons from the two heavy flavour templates . Fig04a.png
Comparison of data and simulation of the distribution of the minimum isolation for muons from the two mis-id templates . Fig04b.png
Template fit to the minimum muon isolation distribution for nine mass bins. The data (points) are compared to the fitted contributions from γ⋆ → μμ (blue) and backgrounds from heavy flavour decays (red) and muon misidentification(green). Fig05.png
Template fit to the minimum muon isolation distribution for five rapidity bins and 10.5 < Mμμ < 20GeV/c2. The first plot shows the fit for the full rapidity range. The data (points) are compared to the fitted contributions from γ⋆ → μμ (blue) and backgrounds from heavy flavour (red) decays and muon misidentification (green). Fig06.png
Template fit to the minimum muon isolation distribution for five rapidity bins and 20 < Mμμ < 40GeV/c2. The first plot shows the fit for the full rapidity range. The data (points) are compared to the fitted contributions from γ⋆ → μμ (blue) and backgrounds from heavy flavour (red) decays and muon misidentification (green). Fig07.png
Differential cross-section for γ⋆ → μμ as a function of Mμμ. The dark shaded (orange) bands correspond to the statistical uncertainties, the light shaded (yellow) band to the statistical and systematic uncertainties added in quadrature. Superimposed are the PYTHIA predictions and the NLO predictions from FEWZ and DYNNLO; they are displaced horizontally for presentation. The shaded vertical band corresponds to the mass region of the Υ which is not included in the measurement. The uncertainties of the NLO predictions contain the PDF uncertainties evaluated at the 68% confidence level and the theoretical errors added in quadrature. The two bins with Mμμ > 40 GeV/c have a cut of pμT > 15 GeV/c for the data and the predictions. The lower plot shows the ratio of the predictions or the uncertainties to the data. Fig08.png
Differential cross-section for γ⋆ → μμ as a function of Mμμ. The dark shaded (orange) bands correspond to the statistical uncertainties, the light shaded (yellow) band to the statistical and systematic uncertainties added in quadrature. Superimposed are NLO predictions from FEWZ with the PDF sets from MSTW08, NNPDF and CTEQ; they are displaced horizontally for presentation. The NLO uncertainties correspond to the PDF uncertainties evaluated at the 68% confidence level. The two bins with Mμμ > 40 GeV/c have a cut of pμT > 15 GeV/c for the data and the predictions. Fig09.png
Differential cross-section for γ⋆ → μμ as a function of y for the mass region of the dimuon system 10.5 - 20 GeV. The dark shaded (orange) bands correspond to the statistical uncertainties, the light shaded (yellow) band to the statistical and systematic uncertainties added in quadrature. The shaded vertical band corresponds to the mass region of the Υ which is not included in the measurement. Superimposed are NLO predictions from FEWZ with the PDF sets from MSTW08, NNPDF and CTEQ; they are displaced horizontally for presentation. The NLO uncertainties correspond to the PDF uncertainties evaluated at the 68% confidence level. Fig10a.png
Differential cross-section for γ⋆ → μμ as a function of y for the mass region of the dimuon system 20 - 40 GeV. The dark shaded (orange) bands correspond to the statistical uncertainties, the light shaded (yellow) band to the statistical and systematic uncertainties added in quadrature. The shaded vertical band corresponds to the mass region of the Υ which is not included in the measurement. Superimposed are NLO predictions from FEWZ with the PDF sets from MSTW08, NNPDF and CTEQ; they are displaced horizontally for presentation. The NLO uncertainties correspond to the PDF uncertainties evaluated at the 68% confidence level. Fig10b.png

-- TaraShears - 18-Sep-2012

Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf Fig01a.pdf r1 manage 15.9 K 2012-09-18 - 16:22 TaraShears  
PNGpng Fig01a.png r1 manage 64.6 K 2012-09-18 - 16:22 TaraShears  
PDFpdf Fig01b.pdf r1 manage 17.0 K 2012-09-18 - 16:22 TaraShears  
PNGpng Fig01b.png r1 manage 124.8 K 2012-09-18 - 16:22 TaraShears  
PDFpdf Fig01c.pdf r1 manage 16.6 K 2012-09-18 - 16:22 TaraShears  
PNGpng Fig01c.png r1 manage 121.9 K 2012-09-18 - 16:22 TaraShears  
PDFpdf Fig01d.pdf r1 manage 16.8 K 2012-09-18 - 16:22 TaraShears  
PNGpng Fig01d.png r1 manage 66.2 K 2012-09-18 - 16:22 TaraShears  
PDFpdf Fig02.pdf r1 manage 14.9 K 2012-09-18 - 16:22 TaraShears  
PNGpng Fig02.png r1 manage 71.7 K 2012-09-18 - 16:22 TaraShears  
PDFpdf Fig03.pdf r1 manage 16.5 K 2012-09-18 - 16:21 TaraShears  
PNGpng Fig03.png r1 manage 38.2 K 2012-09-18 - 16:21 TaraShears  
PDFpdf Fig04a.pdf r1 manage 15.8 K 2012-09-18 - 16:21 TaraShears  
PNGpng Fig04a.png r1 manage 57.6 K 2012-09-18 - 16:21 TaraShears  
PDFpdf Fig04b.pdf r1 manage 15.9 K 2012-09-18 - 16:21 TaraShears  
PNGpng Fig04b.png r1 manage 58.8 K 2012-09-18 - 16:21 TaraShears  
PDFpdf Fig05.pdf r1 manage 182.0 K 2012-09-18 - 16:21 TaraShears  
PNGpng Fig05.png r1 manage 496.0 K 2012-09-18 - 16:21 TaraShears  
PDFpdf Fig06.pdf r1 manage 123.6 K 2012-09-18 - 16:21 TaraShears  
PNGpng Fig06.png r1 manage 348.9 K 2012-09-18 - 16:21 TaraShears  
PDFpdf Fig07.pdf r1 manage 125.8 K 2012-09-18 - 16:21 TaraShears  
PNGpng Fig07.png r1 manage 294.1 K 2012-09-18 - 16:21 TaraShears  
PDFpdf Fig08.pdf r1 manage 17.2 K 2012-09-18 - 16:21 TaraShears  
PNGpng Fig08.png r1 manage 19.3 K 2012-09-18 - 16:21 TaraShears  
PDFpdf Fig09.pdf r1 manage 15.5 K 2012-09-18 - 16:21 TaraShears  
PNGpng Fig09.png r1 manage 17.8 K 2012-09-18 - 16:21 TaraShears  
PDFpdf Fig10a.pdf r1 manage 15.5 K 2012-09-18 - 16:21 TaraShears  
PNGpng Fig10a.png r1 manage 17.1 K 2012-09-18 - 16:21 TaraShears  
PDFpdf Fig10b.pdf r1 manage 15.5 K 2012-09-18 - 16:21 TaraShears  
PNGpng Fig10b.png r1 manage 17.0 K 2012-09-18 - 16:21 TaraShears  
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