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Santa Fe Polarized Drell -Yan Physics Workshop. Feasibility Study of Pion-induced DY Process in FNAL E906. Wen-Chen Chang (Institute of Physics, Academia Sinica) & Jen-Chieh Peng (UIUC) 11/1/2010. Competition and complementarity. DY acceptance @ COMPASS. - PowerPoint PPT Presentation
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Feasibility Study of Pion-induced DY Process in FNAL E906
Wen-Chen Chang(Institute of Physics, Academia Sinica)
& Jen-Chieh Peng (UIUC)
11/1/2010
Santa Fe Polarized Drell-Yan Physics WorkshopSanta Fe Polarized Drell-Yan Physics Workshop
Competition and complementarity
22/04/23 Oleg Denisov 2
DY acceptance @ COMPASS
22/04/23 Oleg Denisov 3
Prediction for Sivers function as a function of x, COMPASS acceptance in xp and acceptance coverage xπ.vs.xp
COMPASS Acceptance
Sivers Function prediction (M.Anselmino et al)
DY@COMPASS projections I
22/04/23Oleg Denisov
4
5
(Dutta, JCP, Cloet, Gaskell, arXiv:1007.3916)
W+, W- production in P+A collision is also sensitive to flavor-dependent EMC
66
Boer-Mulders function h1┴:
ν(π-Wµ+µ-X)~ [valence h1┴(π)] * [valence
h1┴(p)]
ν(pdµ+µ-X)~ [valence h1┴(p)] * [sea h1
┴(p)]
Azimuthal cos2Φ Distribution in p+p and p+d Drell-Yan
E866 Collab., Lingyan Zhu et al., PRL 99 (2007) 082301; PRL 102 (2009)
182001
Sea-quark BM functions are much smaller than valence quarks
Smallνis observed for p+d D-Y
7
Advantages of 120 GeV Main InjectorThe (very successful) past:
Fermilab E866/NuSeaFermilab E866/NuSea Data in 1996-1997 1H, 2H, and nuclear targets 800 GeV proton beam
The future:
Fermilab E906Fermilab E906 Data taking planned in 2010 1H, 2H, and nuclear targets 120 GeV proton Beam
Cross section scales as 1/s – 7x that of 800 GeV beam
Backgrounds, primarily from J/ decays scale as s– 7x Luminosity for same detector
rate as 800 GeV beam
50x statistics!!50x statistics!!
Fixed Target
Beam lines
Tevatron 800 GeV
Main Injector
120 GeV
8
E906 Spectrometer
Solid iron magnet• Reuse SM3 magnet coils• Sufficient Field with reasonable coils • Beam dumped within magnet
25m
Solid Iron
Focusing Magnet,
Hadron absorber
and beam dump
4.9m
Mom. Meas.
(KTeV Magnet)
Had
ron
Abs
orbe
r
Station 1:
Hodoscope array
MWPC tracking
Station 2 and 3:
Hodoscope array
Drift Chamber tracking
Station 4:
Hodoscope array
Prop tube tracking
Liquid H2, d2, and solid targets
Experimental Challenge: Higher probability of muonic decay for the
produced hadrons. Larger multiple scattering for the muon
traveling through hadron absorber and solid magnet.
Worse duty factor for beam structure. Higher singles rates.
Experimental Challenge: Higher probability of muonic decay for the
produced hadrons. Larger multiple scattering for the muon
traveling through hadron absorber and solid magnet.
Worse duty factor for beam structure. Higher singles rates.
9
Extracting d-bar/-ubar From Drell-Yan ScatteringRatio of Drell-Yan cross sections
(in leading order—E866 data analysis confirmed in NLO)
Global NLO PDF fits which include E866 cross section ratios agree with E866 results
Fermilab E906/Drell-Yan will extend these measurements and reduce statistical uncertainty.
E906 expects systematic uncertainty to remain at approx. 1% in cross section ratio.
Acceptance sitting at large x_beam due to the small beam energy. Acceptance sitting at large x_beam due to the small beam energy.
10
Extracting d-bar/-ubar From Drell-Yan ScatteringRatio of Drell-Yan cross sections
(in leading order—E866 data analysis confirmed in NLO)
Global NLO PDF fits which include E866 cross section ratios agree with E866 results
Fermilab E906/Drell-Yan will extend these measurements and reduce statistical uncertainty.
E906 expects systematic uncertainty to remain at approx. 1% in cross section ratio.
Outline of Feasibility Study• Momentum profile of secondary beams from 120-GeV
primary proton hitting 400mm Be target. Proton flux is assumed to be 1*1012 /per spill.
• Drell-Yan cross sections from beam interacting with LH2 target.
• E906 acceptance evaluated by E906 FastMC.• Final yield (= # of beam * # of target/area * DY cross
section * E906 Acceptance) as a function of beam momentum for beam.
• Repeat the study for the case of 980-GeV proton beam.• Summary table.
Momentum Distribution of Secondary Beam
• Primary beam: 120-GeV proton.
• Flux: 1*1012/spill.• Target: 400mm Be.• Acceptance: 2 mrad angular
acceptance (0.25-2.0).• Momentum bite: 1%.• Use “malensek.f” coded by
Chuck Brown.• Reference: Malensek
parameterization (http://ppd.fnal.gov/experiments/e907/notes/MIPPnotes/public/pdf/MIPP0008/MIPP0008.pdf)
Secondary pion+ and pion- beam
Secondary K+ and K- beam
Secondary proton and antiproton beam
Positive- and Negative-charged Secondary Beam (120 GeV)
Significant contamination from protons.
Positive- and Negative-charged Secondary Beam (150 GeV)
DY Cross Section, Target and Acceptance
• DY cross section is calculated utilizing the proton and pion PDF functions in the CENRLIB “pdflib”. A cut on M>1.0 GeV/c2 is imposed.
• 20-inches long LH2 target.• Three configurations of the focusing magnet
(KMAG):– I=1000: Low dimuon-mass– I=2000: Intermediate dimuon-mass– I=2750: Large dimuon-mass
Comparison Between Data and Leading-Order Calculation
EXPeriment = FNAL-444REaction = pi- Nucleus --> mu+ mu- XPlab = 225 GeVAuthor = Anderson et al. Reference = Phys. Rev. Lett. 42 (1979) 944 Target = C
EXPeriment = FNAL-444REaction = pi- Nucleus --> mu+ mu- XPlab = 225 GeVAuthor = Anderson et al. Reference = Phys. Rev. Lett. 42 (1979) 944 Target = C
http://durpdg.dur.ac.uk/cgi-hepdata/drell1/pi-_N_mu/fnal_444/latest_2http://durpdg.dur.ac.uk/cgi-hepdata/drell1/pi-_N_mu/fnal_444/latest_2
Comparison Between Data and Leading-Order Calculation
EXPeriment = FNAL-615REaction = pi- Nucleus --> mu+ mu- XPlab = 252 GeVAuthor = Conway et al. Reference = Phys. Rev. D39 (1989) 92Target = W
EXPeriment = FNAL-615REaction = pi- Nucleus --> mu+ mu- XPlab = 252 GeVAuthor = Conway et al. Reference = Phys. Rev. D39 (1989) 92Target = W
http://durpdg.dur.ac.uk/cgi-hepdata/drell1/pi-_N_mu/fnal_615/latesthttp://durpdg.dur.ac.uk/cgi-hepdata/drell1/pi-_N_mu/fnal_615/latest
Cross Section (nb) of +p Drell-Yan in [M,xf] as a function of Pbeam
P=10 GeV P=20 GeV P=30 GeV
P=60 GeVP=50 GeVP=40 GeV
P=70 GeV P=80 GeV P=90 GeV
Flux of Beam Per Spill
Acceptance of +p Drell-Yanin [M,xf] as a function of Pbeam(I=2000)
P=10 GeV P=20 GeV P=30 GeV
P=60 GeVP=50 GeVP=40 GeV
P=70 GeV P=80 GeV P=90 GeV
Final Yield of +p Drell-Yanin [M,xf] as a function of Pbeam(I=2000)
P=10 GeV P=20 GeV P=30 GeV
P=60 GeVP=50 GeVP=40 GeV
P=70 GeV P=80 GeV P=90 GeV
Final Yield of +p Drell-Yanas a function of Pbeam (I=2000)
From [M,xf]
Accepted +p Drell-Yan Eventsat Pbeam =80 GeV (I=2000)
Mass coverageof 4-6 GeV/c2.
Accepted +p Drell-Yan Eventsat Pbeam =80 GeV (I=2000)
Good coverageof large x_pion.
Positive- and Negative-charged Secondary Beam (980 GeV)
Final Yield of +p Drell-Yanin [M,xf] as a function of Pbeam(I=2000)
P=100 GeV P=150 GeV P=200 GeV
P=350 GeVP=300 GeVP=250 GeV
P=400 GeV P=450 GeV P=500 GeV
Final Yield of -+p Drell-Yanas a function of Pbeam (I=2000)
From [M,xf]
Accepted -+p Drell-Yan Eventsat Pbeam =350 GeV (I=2000)
Bad coverageof large mass region.
Accepted -+p Drell-Yan Eventsat Pbeam =350 GeV (I=2000)
Summary TableE906120 GeV
E906980 GeV
COMPASS
Meson Beam flux 3*10^6 (at 80 GeV)
4*10^8 (at 350 GeV)
6*10^7 (at 106 GeV)
Instantaneous luminosity
6.5*10^30/cm2/spill 8.6*10^32/cm2/spill 1.2*10^32/cm2/sec
DY cross section 0.02*10^-33 cm2 2*10^-33 cm2 0.7*10^-33 cm2
Acceptance 0.05 0.2 0.17
Yield per spill 6*10^-6 3.5*10^-1 1.4*10^-1
Total yield for one year*
1*10^0 5.6*10^4 2*10^4
Audit Too small yield. Accepted mass range too low.
*:at a rate of 1*10^12 protons per spill, 60 spills per hour, 100 hours per week, and 26 weeks of running per year.This yields an integrated proton intensity of 1.6*10^17 protons per year. (FERMILAB-TM-2108)
Low pion beam intensity Less hadron absorber Better mass resolutionLow pion beam intensity Less hadron absorber Better mass resolution
Measurement of Low-Mass Pion-induced Drell-Yan
Accepted +p Drell-Yan Eventsat Pbeam =80 GeV (I=I000)
An enhancement of yield x30, compared to that of I=2000.
Summary• A extremely small yield of pion-induced DY
measurement (~1/per year) at intermediate-mass region is estimated under the current beam and detector configuration for FNAL E906.
• Possible ways for increasing the production rate:– Increase of beam intensity: x10– Increase of momentum bite: x5 (1% 5%)– Increase of target length: x2– Usage of NH3 target: x5– Optimization of detection acceptance: x2
• Measurement of low-mass DY events is possible and interesting.
