MARATHON ratio analysis
Transcript of MARATHON ratio analysis
MARATHON ratio analysis
Tyler KutzStony Brook University
March 23, 2019
2nd Workshop on Quantitative Challenges in SRC and EMC ResearchBoston, MA
1 / 11
1. Introduction
2. Target density correction
3. Radiative correction
4. Tritium β-decay correction
5. Ratios
2 / 11
Introduction
MARATHON
• Measure σ(3H)/σ(3He) to extract Fn2 /Fp2
Extraction from deuterium and proton...
np p
n
pn
np
p• Sensitive to absolute magnitude of
nuclear effects
• Large model dependence at high x
MARATHON extraction...
np p
n
pn
np
p
• Sensitive to relative magnitude ofnuclear effects
• Reduced model dependence at high x
• Measure σ(3H)/σ(2H) and σ(3He)/σ(2H) to observe EMC effectin A = 3 nuclei
3 / 11
Introduction
Status of ratio analysis
• Extracting three ratios:
• 3H/3He (Fn2 /Fp2 , d/u)
• 3H/2H, 3He/2H (EMC effect)
• Data covers range 0.2 < x < 0.8
• Status of ratio analysis:
• Ratios show good stability to changes in cuts, corrections
• Converging on first results for APS April meeting
4 / 11
Target density correction
Density fluctuation
Credit: Nathaly Santiesteban, et al.(a) 3H Density Analysis. (b) 3He Density Analysis.
(c) 2H Density Analysis. (d) 1H Density Analysis.
Figure 10: Density analysis of 3H, 3He, 2H and 1H.
[16] J. Denard, A. Saha, G. Lavessiere, High Accuracy Beam Current MonitorSystem for CEBAF’s Experimental Hall A, Conf. Proc. C0106181 (2001)2326–2328, [,2326(2001)].
[17] K. B. Unser, The Parametric current transformer: A Beam current mon-itor developed for LEP, AIP Conf. Proc. 252 (1992) 266–275. doi:10.1063/1.42124.
Figure 11: Density Factor Ratios.
8
(a) 3H Density Analysis. (b) 3He Density Analysis.
(c) 2H Density Analysis. (d) 1H Density Analysis.
Figure 10: Density analysis of 3H, 3He, 2H and 1H.
[16] J. Denard, A. Saha, G. Lavessiere, High Accuracy Beam Current MonitorSystem for CEBAF’s Experimental Hall A, Conf. Proc. C0106181 (2001)2326–2328, [,2326(2001)].
[17] K. B. Unser, The Parametric current transformer: A Beam current mon-itor developed for LEP, AIP Conf. Proc. 252 (1992) 266–275. doi:10.1063/1.42124.
Figure 11: Density Factor Ratios.
8
(a) 3H Density Analysis. (b) 3He Density Analysis.
(c) 2H Density Analysis. (d) 1H Density Analysis.
Figure 10: Density analysis of 3H, 3He, 2H and 1H.
[16] J. Denard, A. Saha, G. Lavessiere, High Accuracy Beam Current MonitorSystem for CEBAF’s Experimental Hall A, Conf. Proc. C0106181 (2001)2326–2328, [,2326(2001)].
[17] K. B. Unser, The Parametric current transformer: A Beam current mon-itor developed for LEP, AIP Conf. Proc. 252 (1992) 266–275. doi:10.1063/1.42124.
Figure 11: Density Factor Ratios.
8
(a) 3H Density Analysis. (b) 3He Density Analysis.
(c) 2H Density Analysis. (d) 1H Density Analysis.
Figure 10: Density analysis of 3H, 3He, 2H and 1H.
[16] J. Denard, A. Saha, G. Lavessiere, High Accuracy Beam Current MonitorSystem for CEBAF’s Experimental Hall A, Conf. Proc. C0106181 (2001)2326–2328, [,2326(2001)].
[17] K. B. Unser, The Parametric current transformer: A Beam current mon-itor developed for LEP, AIP Conf. Proc. 252 (1992) 266–275. doi:10.1063/1.42124.
Figure 11: Density Factor Ratios.
8
• Beam-induced density fluctuationparameterized by quadratic function
• Details: arXiv:1811.12167(submitted to NIMA)
• Effect on ratios:
• Correction ≤5%• Uncertainty ≤0.5%
5 / 11
Radiative correction
Model input
Credit: Hanjie Liu
Radiative correction requires input model:
• F d2 , F p2
1. Bodek2. NMC 1995 (Phys. Lett. B364 107-115,1995)
• 3H, 3He EMC ratio
1. Kulagin & Petti (no isoscalar corrections)2. SLAC EMC (isoscalar)
• SLAC EMC requires Fn2 /Fp2 to remove isoscalar correction
1. Fn2 /Fp2 = 1− 0.8x
2. CJ153. NMC 1992 (Nucl. Physics. B 371(1992) 3-31)1
Notation example:122 = Bodek + SLAC EMC + CJ15
1Neglects nuclear effects in 2H; not valid at high x6 / 11
Radiative correction
Model dependent uncertainty
0.2 0.3 0.4 0.5 0.6 0.7 0.8
x
0.998
1.000
1.002
1.004
RC
rati
o
H3/H2111/211
121/122
121/123
0.2 0.3 0.4 0.5 0.6 0.7 0.8
x
0.996
0.997
0.998
0.999
1.000
RC
rati
o
He3/H2
111/211
121/122
121/123
0.2 0.3 0.4 0.5 0.6 0.7 0.8
x
0.998
1.000
1.002
1.004
1.006
1.008
1.010
RC
rati
o
H3/He3111/211
121/122
121/123
• Model dependence of EMC ratios <0.5%
• Neglecting high-x NMC, model dependence of 3H/3He <0.5%
7 / 11
Tritium β-decay correction
Target evolution
0 25 50 75 100 125 150 175 200
Days since Oct 23, 2017
0.00
0.01
0.02
0.03
f H
Boiling
MARATHON
SRC
• Tritium β-decays with half life τ1/2 = 4500± 8 days
• Parameterize helium contamination by helium fraction:
fH =nH(t)
ntot=n0H + n0
T (1− e−t/τ )
ntot
• fH ≈ 3% by end of spring run
8 / 11
Tritium β-decay correction
Correction and uncertainty
Can obtain pure tritium yield in terms of raw yield Yraw and helium yield YH :
YT = Yraw
(1
1− 〈fH〉
)− YH
(〈fH〉
1− 〈fH〉
)where 〈fH〉 is charge-weighted helium fraction:
〈fH〉 =
∑QifH,i∑Qi
Effect on ratios:
• 〈fH〉 ≤ 2.5%
• Uncertainty ≤ 0.5%
9 / 11
Ratios
D/p ratio
0.20 0.23 0.25 0.28 0.30 0.33 0.35xBj
1.55
1.60
1.65
1.70
σ(2
H)/σ
(1H
)
MARATHON D/p ratio
PRELIMIN
ARY
10 / 11
Ratios
A = 3 ratios
11 / 11