Download - Kaons P ropagation T hrough N uclei
KaonsKaons P Propagation ropagation Through NucleiThrough Nuclei
NuruzzamanMississippi State
University
This work is sponsored by the Department of Energy
Office of ScienceGrant No.:DE-FG02-07ER41528
Jefferson Lab Hall C Users Meeting
31st January, 2009
Medium Energy Physics GroupAdvisor: Dr.Dipangkar Dutta
(http://ra.msstate.edu/~dd285/mep.html)
OutlineOutline
Nuclear Transparency
Nuclear Transparency with Pions & Kaons
Analysis
Preliminary Results
Nuclear TransparencyNuclear Transparency
Ratio of cross-sections for exclusive processes from nuclei to those from nucleons is termed as Nuclear Transparency
= Free (nucleon) cross-section
= Nuclear cross-section
Experimentally = 0.72 – 0.78, for p,k,
parameterized as = .˙.˙.. T= Aα-1
OutlineOutline
Nuclear Transparency
Nuclear Transparency with Pions & Kaons
Analysis
Preliminary Results
Transparency Experiment withTransparency Experiment with
Experiment ran in July `04 and December `04 at Jefferson Lab
Data collected on LH2, LD2, 12C, 63Cu, and 197Au at Pπ of 2.8, 3.2, 3.4, 4.0 and 4.4 (GeV/c) Q2 of 1.1, 2.15, 3.0, 4.0 and 4.7 (GeV/c)2
JLab Experiment E01-107: A(e,e΄ )
The experiment was measuring pion transparency, however one gets kaons along with pions during data collection because kaons fall
within the coincidence window.
Spokespersons : D. Dutta & Rolf Ent
PionsPions KaonsKaons//
Hall CHall C
HMS- High Momentum SpectrometerSOS- Short Orbit Spectrometer
SOS
HMS
G0
OutlineOutline
Nuclear Transparency
Nuclear Transparency with Pions & Kaons
Analysis
Preliminary Results
JLab Experiment E01-107 JLab Experiment E01-107 Typical coincidence time spectrum showing the
different particles detected
Kaon transparency from electro-production has never been measured before!!!
Coincidence time = Time taken by electron to reach SOS - Time taken by hadrons to reach HMS (within a 30ns window)
π
K+p
Coincidence Time (ns)
Particle Identification Particle Identification in the HMSin the HMS
Gas Cerenkov (Perflurobutane at 1 atm.)
(for pi/k separation)
Aerogel Cherenkov (Aerogel2 of n = 1.015)
(for k/p separation)
eA
Λ
e´
missing massA-
1
Particle Identification Particle Identification in the HMSin the HMS
e + p e’+K+ + Λ
e + A e’+K+ + Λ + X
Ee + Mp = Ee׳ + EK+ +EΛ
Pe + 0 = Pe’ + PK+ + PΛ
Energy & Momentum Conservation
Mass of Λ is MΛ = [EΛ2 - PΛ
2 ]1/2
Reactions
MΛ = 1.115 GeV/c2
MΣ = 1.119 GeV/c2
•Missing Mass: 1.10<Mx <1.15 for Λ,1.17<Mx <1.22 for Σ•Coincidence Time: abs(cointime+58.63)<0.26•Gas Cherenkov:SOS, N(p.e)>1; HMS, N(p.e)<1•Aerogel Cherenkov:HMS, N(p.e)<0•Other acceptances Hsyptar, hsxptar, hsdelta, ssdelta
Kaons after application of all constraints for H
target
Pions, Protons, Kaons (in
coincidence time vs missing mass ) using a loose Constraints
Pions
Kaons
Protons
MΛ= 1.115
MΣ= 1.119
Before & After Application of Constraints Before & After Application of Constraints on Kaon(Liquid Hydrogen) Dataon Kaon(Liquid Hydrogen) Data
Experimental Simulation Experimental Simulation “SIMC”“SIMC”
Ingredients of SIMC:
1. Realistic Models of the magnetic spectrometers including multiple scattering and energy loss in all intervening material encountered by the particles.
2. Decay of kaons in flight, and radiative corrections for all particles.
3. Model of the electro production of kaons from free protons
4. For heavier targets the free proton model is convoluted with a realistic spectral function for each target. Spectral function = probability of finding a proton inside the nucleus with a certain energy and momentum.
Transparency to be extracted asModelpExptp
ModelAExptA
σσ
σσ=T
/
/
Comparison of Liquid Hydrogen Data vs Comparison of Liquid Hydrogen Data vs Simulation(SIMC)applying all constraintsSimulation(SIMC)applying all constraints
Red – SIMCBlue – Data
All particle identification and acceptance constraints applied
σ = σ (Q2, W, t, ϕpq)
Q2 = Four MomentumTransferred Squared
Q2 Q2
Q2 Q2
SIMC Λ SIMC Σ
DataSIMC Λ + Σ
&Data
The ratio of Λ/Σ is determined from the LH2 data
Q2=1.1 GeV2 : 15.6 Q2=2.2 GeV2 : 9.7 Q2=3.0 GeV2 : 6.4
Comparison of Liquid Hydrogen Data vs Comparison of Liquid Hydrogen Data vs Simulation(SIMC)applying all constraintsSimulation(SIMC)applying all constraints
Red – SIMCBlue – Data
All particle identification and acceptance constraints applied
σ = σ (Q2, W, t, ϕpq)
W = Centre ofMass Energy w w
w w
SIMC Λ SIMC Σ
DataSIMC Λ + Σ
&Data
Comparison of Liquid Hydrogen Data vs Comparison of Liquid Hydrogen Data vs Simulation(SIMC)applying all constraintsSimulation(SIMC)applying all constraints
Red – SIMCBlue – Data
All particle identification and acceptance constraints applied
σ = σ (Q2, W, t, ϕpq)
t = Mandelstam Variable
t t
t t
SIMC Λ SIMC Σ
DataSIMC Λ + Σ
&Data
Comparison of Liquid Hydrogen Data vs Comparison of Liquid Hydrogen Data vs Simulation(SIMC)applying all constraintsSimulation(SIMC)applying all constraints
Red – SIMCBlue – Data
All particle identification and acceptance constraints applied
σ = σ (Q2, W, t, ϕpq)
ϕpq= Angle BetweenReaction Plane &Scattering Plane ϕpq
SIMC Λ SIMC Σ
DataSIMC Λ + Σ
&Data
ϕpq
ϕpq ϕpq
Pions, Protons & Kaons before application of all constraints for LD
target
Kaons separated after application of all
constraints on LD target
•Missing Mass: 1.09<Mx <1.22•Coincidence Time: abs(cointime+58.63)<0.26•Gas Cherenkov:SOS, N(p.e)>1; HMS, N(p.e)<1•Aerogel Cherenkov:HMS, N(p.e)<0•Other acceptances Hsyptar, hsxptar, hsdelta, ssdelta
Before & After Application of Constraints Before & After Application of Constraints on Kaon(Liquid Deuterium) Dataon Kaon(Liquid Deuterium) Data
Red – SIMCBlue – Data
All particle identification and acceptance constraints applied
Comparison of Liquid Deuterium Data vs Comparison of Liquid Deuterium Data vs Simulation(SIMC)applying all constraintsSimulation(SIMC)applying all constraints
Q2 = Four Momentum Transferred Squared
Q2
Q2 Q2
Q2
SIMC Λ SIMC Σ
DataSIMC Λ + Σ
&Data
σ = σ (Q2, W, t, ϕpq)
The ratios of Λ/Σ obtained from LH2 data are used to add the Λ-SIMC and Σ-SIMC yields
Red – SIMCBlue – Data
All particle identification and acceptance constraints applied
Comparison of Liquid Deuterium Data vs Comparison of Liquid Deuterium Data vs Simulation(SIMC)applying all constraintsSimulation(SIMC)applying all constraints
W = Centre of Mass Energy
SIMC Λ SIMC Σ
DataSIMC Λ + Σ
&Data
w w
w w
σ = σ (Q2, W, t, ϕpq)
Red – SIMCBlue – Data
All particle identification and acceptance constraints applied
Comparison of Liquid Deuterium Data vs Comparison of Liquid Deuterium Data vs Simulation(SIMC)applying all constraintsSimulation(SIMC)applying all constraints
t = Mandelstam Variable
SIMC Λ SIMC Σ
DataSIMC Λ + Σ
&Data
t t
t t
σ = σ (Q2, W, t, ϕpq)
Red – SIMCBlue – Data
All particle identification and acceptance constraints applied
Comparison of Liquid Deuterium Data vs Comparison of Liquid Deuterium Data vs Simulation(SIMC)applying all constraintsSimulation(SIMC)applying all constraints
SIMC Λ SIMC Σ
Data SIMC Λ + Σ&
Data
ϕpq= Angle BetweenReaction Plane &Scattering Plane
/
/
Expt ModelAA
Expt Modelpp
T
ϕpq
ϕpq ϕpq
ϕpq
σ = σ (Q2, W, t, ϕpq)
Red – SIMCBlue – Data
All particle identification and acceptance constraints applied
Comparison of Data vs Simulation(SIMC)applying Comparison of Data vs Simulation(SIMC)applying all constraints for Other Targetsall constraints for Other Targets
Q2 = Four Momentum Transferred Squared
Q2
Q2 Q2
SIMC Λ + Σ&
Data
σ = σ (Q2, W, t, ϕpq)Carbon Copper
Gold
OutlineOutline
Nuclear Transparency
Nuclear Transparency with Pions & Kaons
Analysis
Preliminary Results
Systematic Uncertainties of E01107Systematic Uncertainties of E01107
3.9 3.8TOTAL
2.0 1.0Spectral Function
2.0 1.0Iteration
2.0 0.5Acceptance
1.0collimator
1.0 0.5Radiative Corrections
0.5Pauli Blocking
1.0 0.5Pion Decay
0.5 2.52.5Cut dependence
0.1 0.1Beam Energy
2.0 0.5Pion Absorption
0.5 0.5Tracking(HMS+SOS)
0.1Dead time correction
0.7Trigger(HMS+SOS)
0.1Coin blocking
0.5Target thickness
0.5 0.3Charge
0.4 - 0.7 2.0.0Particle ID
scale(%) total(%) point-to-point (%) Item
5.4
LD2 - Black
Carbon - Red
Copper - Green
Gold - Blue
Nuclear Transparency Nuclear Transparency vsvs Q Q22
Q2 ( GeV/c2 )
Preliminary Result
Cu, C, LD2 are shifted by -0.05,0.05,-0.10 in Q2 respectively
Analysis Plan Analysis Plan
•Determine the model dependent uncertainty
•Compare with theoretical calculations(Please contact your favorite theorist )
•Write paper & publish results
This work is sponsored by the Department of Energy
Office of ScienceGrant No.: DE-FG02-07ER41528
ThanThank Youk You
Red – SIMCBlue – Data
All particle identification and acceptance constraints applied
σ = σ (Q2, W, t, phipq)
Comparison of Liquid Deuterium Data vs Comparison of Liquid Deuterium Data vs Simulation(SIMC)applying all constraintsSimulation(SIMC)applying all constraints
Missing Massmissing mass
missing mass
missing mass
missing mass
SIMC Λ SIMC Σ
Data SIMC Λ + Σ&
Data