Coherent-Rho 0 Production in Neutrino Neutral-Current Interactions - - PowerPoint PPT Presentation

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Coherent-Rho 0 Production in Neutrino Neutral-Current Interactions - - PowerPoint PPT Presentation

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Coherent-Rho 0 Production in Neutrino Neutral-Current Interactions A 0 A Chris Kullenberg Sanjib R. Mishra July 7, 2015 Coh 0 Production Kullenberg, Mishra July 7, 2015 1 / 52 A A Neutrino-Induced

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SLIDE 1

Coherent-Rho0 Production in Neutrino Neutral-Current Interactions

νµ A ֌ νµ ρ0 A Chris Kullenberg Sanjib R. Mishra July 7, 2015

Kullenberg, Mishra Cohρ0 Production July 7, 2015 1 / 52

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SLIDE 2

Neutrino-Induced Coherent Rho Production:

νµ A ֌ µ ρ A ∗ Structure of Weak-Current and its Hadronic-Content: Piketty-Stodolsky Model ⇒ CVC Vector meson Dominance (VMD)

P u¯ d W + A(p) νµ(l) A(p′) ρ+ µ(l′)

d 3σ νµA → µ−ρ+A dQ2dνdt = G2

F

4π2 f 2

ρ

1 − ǫ |q| E 2

ν

  • Q

Q2 + m2

ρ

2

(1 + ǫR)

  • dσT(ρ+A → ρ+A)

dt

  • where GF is the weak coupling constant, Q2 = −q2 = −(k − k′)2, ν = Eν − Eµ, the

polarization parameter ǫ =

4EνEµ−Q2 4EνEµ+Q2+2ν2 , and R = dσL/dt dσT /dt with σL and σT as the

longitudinal and transverse ρ-nucleus cross-sections. fρ is the coupling constant of the ρ meson to the W boson.

Kullenberg, Mishra Cohρ0 Production July 7, 2015 2 / 52

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SLIDE 3

Coherent-ρ0 -vs- Coherent-ρ+ : ∗ Coherent ρ± observed by E546, E632, SKAT, and BEBC Precision of ±25–30% ∗ Measurement of Coherent-ρ0 has never been reported. Inclusive-ρ0 has been measured: the most precise measurement is by NOMAD ( Nucl. Phys. B601, 3[2001] ) ∗ Simple relation between Coherentρ0 & Coherentρ± ֌ d3σ(νµA → νµρ0A) dQ2dνdt = 1 2

  • 1 − 2 sin2 θW

2

  • d3σ(νµA → µ−ρ+A)

dQ2dνdt

  • ⇒ σ(Coherent-ρ0) ∼

= 0.15× σ(Coherent-ρ+)

Kullenberg, Mishra Cohρ0 Production July 7, 2015 3 / 52

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SLIDE 4

Conditions for Coherent Events:

∗ Wavelength of exchange particle compatible with entire nucleus (diffractive, low Q2) ∗ Nucleus recoils as a whole ∗ Nucleus remains in ground state ∗ No transfer of quantum numbers ∗ Generally very forward mesons

Kullenberg, Mishra Cohρ0 Production July 7, 2015 4 / 52

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SLIDE 5

The NOMAD Detector ∗ High resolution tracking ∗ Fine-grained calorimeter ∗ Unambiguous charge separation

Kullenberg, Mishra Cohρ0 Production July 7, 2015 5 / 52

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SLIDE 6

Signal

∗ π−π+ with little else (ππ) vector (P, θ) consistent with Coherent-ρ0 such that ζππ =EV 0 ∗ (1 − cos θV 0) ≤ Cut (0.075)

Background

[1] NC-induced (NC-DIS) background ⇒ 2-Track (+,-) [2] CC-induced (CC-DIS) background ⇒ 2-Track (+,-) SPACER where ”-” is a µ− w/o µID [3] Outside-Background (OBG) ⇒ K0s from outside-interactions

Control Sample: CC Data Simulator Correction

∗ νµ-CC events where the µ− identified and then ’removed’; the remaining hadronic (+,-) tracks subjected to the analysis.

Kullenberg, Mishra Cohρ0 Production July 7, 2015 6 / 52

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SLIDE 7

What we are looking for: Coherent-ρ0 Candidate Event Pπ+=3.1; Pπ−=2.3 (GeV) Mππ= 0.74 GeV ζππ= 0.008

π+ π−

Kullenberg, Mishra Cohρ0 Production July 7, 2015 7 / 52

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SLIDE 8

Eππ

Eππ (GeV) (200MeV)

0.01 0.02 0.03 0.04 0.05 2 4 6 8 10 12 14 16 18 20 Number of Events

⇒ E ππ ≥ 2GeV

NC-DIS CC-DIS

✟ ✟ ✙

Cohρ0

Kullenberg, Mishra Cohρ0 Production July 7, 2015 8 / 52

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SLIDE 9

φππ

Φπ+- (Deg)

0.02 0.04 0.06 0.08 0.1 0.12 20 40 60 80 100 120 140 160 180 Number of Events

⇒ ⇐

200 ≤ φππ≤ 1600

NC-DIS CC-DIS

Cohρ0

Kullenberg, Mishra Cohρ0 Production July 7, 2015 9 / 52

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SLIDE 10

Analysis of Coherent ρ0 : Kinematic Shape Comparison

Mππ (GeV/c2) 30MeV

0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.25 0.5 0.75 1 1.25 1.5 1.75 2 Number of Events

Mππ

✻

K0s OBG

✲ ✛

∼ 85% of ρ0

ζππ 0.6≤Mππ≤1.0

0.05 0.1 0.15 0.2 0.25 0.3 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 Number of Events

ζππ

NC-DIS

✁ ✁ ☛

CC-DIS

✟ ✟ ✟ ✟ ✙

Cohρ0

0.075

ζππ (

) Kullenberg, Mishra Cohρ0 Production July 7, 2015 10 / 52

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SLIDE 11

Coherent-ρ0 Analysis:

∗ 2-Track (π+π−) Events in Fiducial Volume w/o µ-ID passing kinematic preselection cuts

∗ Calibrate OBG

⇒ 2-Track events with vertex outside ⇒ Normalize it to the K 0 peak

∗ Calibrate the shape of NC-DIS

The most important variable is the shape of ζππ ⇒ Use CC-DS (3-&-4 Track events w. µ); ⇒ The π+π− subjected to the standard selection ⇒ Obtain a MC(NC-DIS) Re-Weight based on Data/MC [Pπ±, Ptπ±, Mππ, ζππ]

∗ Normalize NCDIS (shapes reweighted using Data-Simulator)

⇒ Use φππ distribution with ζππ > 0.075

∗ Result

⇒ Plot Mππ; impose 0.6 ≤ Mππ ≤ 1.0 GeV ⇒ Using ζππ, fit for Cohρ using ≤ 0.1 region ⇒ Check CC-DIS normalization ⇒ Systematic error analysis

Kullenberg, Mishra Cohρ0 Production July 7, 2015 11 / 52

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SLIDE 12

Shape of NC-DIS used in Coherentρ0 Analysis: CC Data-Simulator ∗ νµ-CC with µ−π+π− ∗ DIS weight based upon: [Pπ±, Ptπ±, Mππ, ζππ] ⇒

200 400 600 800 1000 1200 1400 2 4 6 8 10 12 14 16 18 20

Eππ Eππ Eππ

E ππ

Weighted MC Un-weighted MC

Kullenberg, Mishra Cohρ0 Production July 7, 2015 12 / 52

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SLIDE 13

M ππ

200 400 600 800 1000 1200 1400 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

Mππ Mππ Mππ

Weighted MC Un-weighted MC

Kullenberg, Mishra Cohρ0 Production July 7, 2015 13 / 52

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SLIDE 14

ζππ

250 500 750 1000 1250 1500 1750 2000 2250 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5

ζππ ζππ ζππ

Weighted MC Un-weighted MC Signal ⇒

200 400 600 800 1000 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5

ζππ (0.6≤Mππ≤1.0) ζππ (0.6≤Mππ≤1.0) ζππ (0.6≤Mππ≤1.0)

0.6≤Mππ ≤1.0

Kullenberg, Mishra Cohρ0 Production July 7, 2015 14 / 52

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SLIDE 15

Preselection NC-DIS (∼x4 Data) ֌ 0.44M CC-DIS (∼x4 Data) ֌ 1.44M Cohπ+ ֌ 10k Cohρ0 ֌ 1,000 ∗ Fiducial Cut, Muon-Veto, 2-Tracks Sample #-Events NC-DIS (∼x4) 18, 400 CC-DIS (∼x4) 4, 600 Data 39, 500

Kullenberg, Mishra Cohρ0 Production July 7, 2015 15 / 52

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SLIDE 16

Selection ∗ ’Other’ includes QE, Res, Cohπ+, Cohπ0 ∗ Vetos: DC-Veto/tube, Upstream-hanger, V0-from-vertex

Selection NC-DIS∗ CC-DIS∗ OBG Other Cohρ0∗ Total Data Veto/UpHanger 10, 262 2, 498 1, 520 526 395 15, 202 15, 850 Photon Veto 6, 846 1, 506 359 260 368 9, 339 9, 490 200 ≤ φππ ≤ 1600 5, 321 870 255 104 305 6, 854 6, 852

Kullenberg, Mishra Cohρ0 Production July 7, 2015 16 / 52

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SLIDE 17

Normalization of NC Background

Φπ+- (Deg) ζππ>0.075

100 200 300 400 500 20 40 60 80 100 120 140 160 180 Number of Events

NCDIS-Norm

χ2

1.043 ± 0.023

∗Cohρ0 MC ∗NC-MC Bkg(DS-Wt) ∗CC-MC Bkg ∗OBG-K0s Bkg Kullenberg, Mishra Cohρ0 Production July 7, 2015 17 / 52

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SLIDE 18

ζππ

100 200 300 400 500 600 700 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 Number of Events

200 400 600 800 1000 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5

ζππ (0.6≤Mππ≤1.0) ζππ (0.6≤Mππ≤1.0) ζππ (0.6≤Mππ≤1.0)

CC-Data

OBG-K0

✟ ✟ ✙

CC-MC

✁ ✁ ☛

Total BKG

✁ ✁ ☛

ζππ 0.6≤Mππ≤1.0

50 100 150 200 250 300 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 Number of Events

Normalization (Cohρ0)

χ2

(669 ± 116 evts)

0.669±0.116 (17.3%) 0.6≤Mππ ≤1.0

Cohρ0

✟ ✟ ✙

NC-MC

✄ ✄ ✗

∗Cohρ0 MC ∗NC-MC Bkg(DS-Weighted) ∗CC-MC Bkg ∗OBG-K0s Bkg Kullenberg, Mishra Cohρ0 Production July 7, 2015 18 / 52

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SLIDE 19

Mππ (GeV/c2) ζππ≤0.075

50 100 150 200 250 0.25 0.5 0.75 1 1.25 1.5 1.75 2 Number of Events

Coherent Region: ζ ≤ 0.075

∗Cohρ0 MC ∗NC-MC Bkg(DS-Weighted) ∗CC-MC Bkg ∗OBG-K0s Bkg Mππ (GeV/c2) ζππ>0.075

20 40 60 80 100 120 140 160 180 0.25 0.5 0.75 1 1.25 1.5 1.75 2 Number of Events

non-Coherent Region: ζ > 0.075

Kullenberg, Mishra Cohρ0 Production July 7, 2015 19 / 52

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SLIDE 20

Systematic Error ⇒ ∗ Data-Simulator: (Shape of ζ in NC-DIS)

Using only ζ-Wt (which does not describe the ππ system in CC-data well)

⇒ ±0.072 (10.8%) ================================ ∗ NC-DIS:

Using ±2.3% variation (constrained by φππ in the background region)

⇒ ±0.048 (7.17%) ∗ CC-DIS: ⇒ ±0.015 (2.24%)

Kullenberg, Mishra Cohρ0 Production July 7, 2015 20 / 52

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SLIDE 21

Systematic Error ⇒ ∗ OBG (K 0):

With 833 data events used to simulate the OBG, a 3.5% variation in its normalization had a negligible effect on the Cohρ0 normalization.

⇒ ±0.000 (0.0%) ∗ Total Systematic Error: ⇒ ±0.088 (13.2%) ∗ Total Error: ⇒ 0.669 ± 0.116 ± 0.088 (±21.8%)

Kullenberg, Mishra Cohρ0 Production July 7, 2015 21 / 52

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SLIDE 22

Conclusion ⇒ νµ A ֌ νµ ρ0 A ∗ We have conducted a measurement of Coherent-ρ0 production. A clear signal of Coherent-ρ0 is observed. ∗ The analysis is data-driven; the backgrounds are constrained using control samples. ∗ We observe: 669 ± 116(Stat.) ± 88(Syst.) fully corrected Coherent-ρ0 events. ∗ The rate with respect to -CC events (1.44 ∗ 10 6) is: (4.65 ± 1.01) ∗ 10 −4

Kullenberg, Mishra Cohρ0 Production July 7, 2015 22 / 52

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SLIDE 23

Mππ (GeV/c2)

50 100 150 200 250 300 350 400 0.25 0.5 0.75 1 1.25 1.5 1.75 2 Number of Events

Cohρ0

✟ ✟ ✙

OBG-K0

✁ ✁ ☛

NC-MC

✟ ✟ ✯

CC-MC

  • ✠

Total BKG

✟ ✟ ✟ ✙

∗Cohρ0 MC ∗NC-MC Bkg(DS-Weighted) ∗CC-MC Bkg ∗OBG-K0s Bkg Kullenberg, Mishra Cohρ0 Production July 7, 2015 23 / 52

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SLIDE 24

Backup

Kullenberg, Mishra Cohρ0 Production July 7, 2015 24 / 52

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SLIDE 25

M ππ

Mππ (GeV/c2) (30MeV)

20 40 60 80 100 120 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 Number of Events

Cohρ0

✻

K0s

✲ ✛

∼ 85% of ρ0

Kullenberg, Mishra Cohρ0 Production July 7, 2015 25 / 52

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SLIDE 26

What we are looking for: Coherent-ρ0 Candidate Event Pπ+=1.6; Pπ−=2.6 (GeV) Mππ= 0.69 GeV ζππ= 0.028

π+ π−

Kullenberg, Mishra Cohρ0 Production July 7, 2015 26 / 52

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SLIDE 27

What we are looking for: Coherent-ρ0 Candidate Event Pπ+=5.9; Pπ−=1.8 (GeV) Mππ= 0.61 GeV ζππ= 0.024

π+ π−

Kullenberg, Mishra Cohρ0 Production July 7, 2015 27 / 52

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SLIDE 28

Multi-Variate Analysis of the Coh-ρ0 ∗ Identical event selection; DS-Correction applied to the shapes of the NC-DIS. ∗ Form a Likelihood function based upon: 1 LH = [ζππ, φππ] ∗ S Coherent-Region ⇒ LH≥ 0.0 non-Coherent-Region ⇒ LH< 0.0 ∗ Tried 3 other LH functions based upon other variables, all giving similar results.

Kullenberg, Mishra Cohρ0 Production July 7, 2015 28 / 52

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SLIDE 29

200 400 600 800 1000

  • 4
  • 3
  • 2
  • 1

1 2 3 4

LH(ζππ ,Φ12) LH(ζππ ,Φ12) LH(ζππ ,Φ12) LH(ζππ ,Φ12) LH(ζππ ,Φ12) LH(ζππ ,Φ12) LH(ζππ ,Φ12)

Number of Events

LH [ζππ, φππ]

∗Cohρ0 MC ∗NC-MC Bkg(DS-Weighted) ∗CC-MC Bkg ∗OBG-K0s Bkg Kullenberg, Mishra Cohρ0 Production July 7, 2015 29 / 52

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SLIDE 30

Mππ (GeV/c2) LH(ζππ,Φ12)≥0.0

50 100 150 200 250 0.25 0.5 0.75 1 1.25 1.5 1.75 2 Number of Events

Coherent Region: LH ≥ 0.0 0.673±0.116

Signal Cohρ0 ⇒

Mππ (GeV/c2) LH(ζππ,Φ12)<0.0

25 50 75 100 125 150 175 200 0.25 0.5 0.75 1 1.25 1.5 1.75 2 Number of Events

non-Coherent Region: LH < 0.0

∗Cohρ0 MC ∗NC-MC Bkg(DS-Wt) ∗CC-MC Bkg ∗OBG-K0s Bkg Kullenberg, Mishra Cohρ0 Production July 7, 2015 30 / 52

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SLIDE 31

Conclusion of Multi-Variate Analysis of the Coh-ρ0 ∗ Results, Coherent and non-Coherent regions, consistent with those presented earlier. ∗ Tried 3 othe LH functions based upon other variables, all giving similar results. ∗ But unlike the earlier analysis, LH did not yield any deeper insight. Actually, we found it as charming as M.R. but considerably more consistent.

Kullenberg, Mishra Cohρ0 Production July 7, 2015 31 / 52

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SLIDE 32

Analysis with Eππ > 4GeV

Eππ (GeV) (200MeV)

0.01 0.02 0.03 0.04 0.05 2 4 6 8 10 12 14 16 18 20 Number of Events

⇒ E ππ ≥ 4GeV

NC-DIS

✟ ✟ ✙

CC-DIS

✟ ✟ ✙

Cohρ0

Kullenberg, Mishra Cohρ0 Production July 7, 2015 32 / 52

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SLIDE 33

Mππ (GeV/c2)

25 50 75 100 125 150 175 200 225 0.25 0.5 0.75 1 1.25 1.5 1.75 2 Number of Events

Mππ E ππ > 4GeV

∗Cohρ0 MC ∗NC-MC Bkg(DS-Wt) ∗CC-MC Bkg ∗OBG-K0s Bkg Kullenberg, Mishra Cohρ0 Production July 7, 2015 33 / 52

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SLIDE 34

Mππ (GeV/c2) ζππ≤0.075

20 40 60 80 100 120 140 160 0.25 0.5 0.75 1 1.25 1.5 1.75 2 Number of Events

Normalization-Cohρ0

0.620±0.100 Coherent Region: ζ ≤ 0.075

E ππ > 4GeV

∗Cohρ0 MC ∗NC-MC Bkg(DS-Wt) ∗CC-MC Bkg ∗OBG-K0s Bkg Mππ (GeV/c2) ζππ>0.075

20 40 60 80 100 0.25 0.5 0.75 1 1.25 1.5 1.75 2 Number of Events

non-Coherent Region: ζ > 0.075

E ππ > 4GeV

∗Cohρ0 MC ∗NC-MC Bkg(DS-Wt) ∗CC-MC Bkg ∗OBG-K0s Bkg Kullenberg, Mishra Cohρ0 Production July 7, 2015 34 / 52

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SLIDE 35

Conclusion of ‘Eππ> 4GeV -Cut’ Analysis of the Coh-ρ0 ∗ Results, Coherent and non-Coherent regions, consistent with those presented in the standard analysis. ∗ The stingent cut, Eππ> 4GeV , lowers the backgrounds (NC-DIS & CC-DIS), and offers a slightly better statistical error on the Coh-ρ0 signal, but overall error, Stat+Syst, is similar to the analysis with the looser cut.

Kullenberg, Mishra Cohρ0 Production July 7, 2015 35 / 52

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SLIDE 36

Data Simulator: calibrate the shape of NC-DIS:

∗ Select νµ-CC events with 3 and 3-&-4 tracks, including the µ ∗ Obtain a weight for MC(NC-DIS) using DS-Correction=Data/MC [Pπ±, Ptπ±, Mππ, ζππ] ∗ Apply the weight to NC-DIS ∗ Repeat this study: Re-Weight for MC(NC-DIS) using Data/MC [ only ζππ] ∗ 3-Track and (3+4)-Track νµ-CC events yield entirely consistent results ⇒ Use (3+4)-Track sample for the DS-correction

Kullenberg, Mishra Cohρ0 Production July 7, 2015 36 / 52

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SLIDE 37

CC Data-Simulator (Standard Reweight)

200 400 600 800 1000 1200 1400 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

Mππ Mππ Mππ

200 400 600 800 1000 1200 1400 2 4 6 8 10 12 14 16 18 20

Eππ Eππ Eππ Kullenberg, Mishra Cohρ0 Production July 7, 2015 37 / 52

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SLIDE 38

CC Data-Simulator (Standard Reweight)

250 500 750 1000 1250 1500 1750 2000 2250 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5

ζππ ζππ ζππ

200 400 600 800 1000 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5

ζππ (0.6≤Mππ≤1.0) ζππ (0.6≤Mππ≤1.0) ζππ (0.6≤Mππ≤1.0) Kullenberg, Mishra Cohρ0 Production July 7, 2015 38 / 52

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SLIDE 39

CC Data-Simulator: Variant

∗ DIS weight based upon only: [ζππ] Alternative scheme ⇒

200 400 600 800 1000 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5

ζππ (0.6≤Mππ≤1.0) ζππ (0.6≤Mππ≤1.0) ζππ (0.6≤Mππ≤1.0)

ζππ

Weighted MC Un-weighted MC

✟ ✟ ✟ ✙✟ ✟ ✟ ✙

Kullenberg, Mishra Cohρ0 Production July 7, 2015 39 / 52

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SLIDE 40

CC Data-Simulator (Variant)

200 400 600 800 1000 1200 1400 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

Mππ Mππ Mππ

200 400 600 800 1000 1200 1400 2 4 6 8 10 12 14 16 18 20

Eππ Eππ Eππ Kullenberg, Mishra Cohρ0 Production July 7, 2015 40 / 52

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SLIDE 41

Quasi-Exclusive ρ0 in NC

Quasi-Exclusive ρ0 ⇒ 1.192±0.142 Using Cohρ0 as an efficeincy model ⇒ 1, 192±142 Events

Mππ (GeV/c2)

50 100 150 200 250 300 350 400 0.25 0.5 0.75 1 1.25 1.5 1.75 2 Number of Events

∗Quasi-Exclusive ρ0 ∗NC-MC Bkg ∗CC-MC Bkg ∗OBG-K0 Bkg

SPACER

Kullenberg, Mishra Cohρ0 Production July 7, 2015 41 / 52

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SLIDE 42

φππ with (0.6 ≤ Mππ ≤ 1.0)

Φπ+- (Deg) 0.6≤Mππ≤1.0 ζππ>0.075

50 100 150 200 250 300 20 40 60 80 100 120 140 160 180 Number of Events

Background Region

Φπ+- (Deg) 0.6≤Mππ≤1.0 ζππ≤0.075

20 40 60 80 100 120 140 160 20 40 60 80 100 120 140 160 180 Number of Events

Signal Region

Kullenberg, Mishra Cohρ0 Production July 7, 2015 42 / 52

slide-43
SLIDE 43

ζππ 0.6≤Mππ≤2.0

50 100 150 200 250 300 350 400 450 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 Number of Events

∗Cohρ0 MC ∗NC-MC Bkg(DS-Weighted) ∗CC-MC Bkg ∗OBG-K0s Bkg Kullenberg, Mishra Cohρ0 Production July 7, 2015 43 / 52

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SLIDE 44

Pπ Asym 0.6≤Mππ≤1.0 ζππ≤0.075

10 20 30 40 50 60 70

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 Number of Events

Momentum Asymmetry in Signal Region

Kullenberg, Mishra Cohρ0 Production July 7, 2015 44 / 52

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SLIDE 45

Φπ+- (Deg)

50 100 150 200 250 300 350 400 20 40 60 80 100 120 140 160 180 Number of Events

φππ Used to Normalize CC-MC

Kullenberg, Mishra Cohρ0 Production July 7, 2015 45 / 52

slide-46
SLIDE 46

XVR

50 100 150 200 250 300 350 400 450

  • 100

100 Number of Events

YVR

100 200 300 400 500

  • 100

100 Number of Events

ZVR (cm) (10 cm)

50 100 150 200 250 300 350 100 200 300 400 500 Number of Events

∗Cohρ0 MC ∗NC-MC Bkg(DS-Weighted) ∗CC-MC Bkg ∗OBG-K0s Bkg Kullenberg, Mishra Cohρ0 Production July 7, 2015 46 / 52

slide-47
SLIDE 47

Pππ (GeV/c)

100 200 300 400 500 600 700 800 2 4 6 8 10 12 14 16 18 20 Number of Events

Ptππ (GeV/c)

50 100 150 200 250 300 350 400 0.5 1 1.5 2 2.5 3 Number of Events

∗Cohρ0 MC ∗NC-MC Bkg(DS-Weighted) ∗CC-MC Bkg ∗OBG-K0s Bkg Kullenberg, Mishra Cohρ0 Production July 7, 2015 47 / 52

slide-48
SLIDE 48

Mππ (GeV/c2)

50 100 150 200 250 300 350 400 0.25 0.5 0.75 1 1.25 1.5 1.75 2 Number of Events

∗Cohρ0 MC ∗NC-MC Bkg(DS-Wt) ∗CC-MC Bkg ∗OBG-K0s Bkg

⇐

A beautiful distribution in ν-measurement! Kullenberg, Mishra Cohρ0 Production July 7, 2015 48 / 52

slide-49
SLIDE 49

Meson-Nucleus Absorption: Following the Rein-Sehgal model of meson-nucleus absorption, dσT(ρ+A → ρ+A) dt = A2 16πσ2(hn) exp(−b|t|)Fabs where σ(hn) is the ’hadron-nucleon’ cross-section with the energy of the hadron ≃ ν, b = R2/3 such that R = R0A1/3, with R0 = 1.12fm and the absorption factor Fabs = 0.47 ± 0.03. ∗ Coherence Condition:

  • |t| ≤ 1/RNucleus

Kullenberg, Mishra Cohρ0 Production July 7, 2015 49 / 52

slide-50
SLIDE 50

Simulation of Coherent-ρ

∗ Stand-alone program checked agains the NEGLIB Coherent-ρ0 written by the Australian Group (Hyett & Varvell) ∗ Coherent-ρ0 ∼ 0.15×Coherent-ρ+

σ( Cohρ+) [10 −36cm2]

Kullenberg, Mishra Cohρ0 Production July 7, 2015 50 / 52

slide-51
SLIDE 51

(10 −36cm2) E ν (GeV)

Kullenberg, Mishra Cohρ0 Production July 7, 2015 51 / 52

slide-52
SLIDE 52

Cohρ+ & Cohπ+ Xsec (10 −40 cm2 )

Cohρ+ Cohπ+

Cohρ+ / Cohπ+

Kullenberg, Mishra Cohρ0 Production July 7, 2015 52 / 52