NuFact04 - Osaka, Japan

WG2 Summary - Part 1Neutrino Scattering Physics Topics

Conveners: Makoto Sakuda and Jorge G. Morfín

Hadron production cross section p + A (Be,C,Al,Fe) +- + X

• Previous neutrino cross sections in the few GeV region are published using only 100-1000 events and using the old hadron production cross sections with 10-20% errors. K2K/MiniBOONE have >10K-100K events.

• This is a fundamental input to not only neutrino beam and atmospheric neutrino flux calculations but also any detector simulators.

• We need better accuracy at a few % (<10%).

pn +→+ −μν μ

D.Casper (Prenary talk on July 30)(Eν) =N(Eν)/(F(Eν) nTarget)

np +→+ +μν μ

_

pn +→+ −μν μ

K2K/MiniBOONE have enough statistics to measure cross sections. All they need is flux.

MiniBOONEK2K

SciBar (Carbon)1-track

SciBar (Carbon)2-track

SciFi (Water) has QE. KT (Water) NC0

WG2 July 31

New experiments (BNL-E910, HARP, MIPP) on hadron production

1. HARP measurements of pion yield

for neutrino experiments I.Kato (Kyoto)

2. Pion Production on Be at 6, 12 and 18 GeV in Brookhaven E910 -- J.Link (Columbia)

HARP Detectors

Beam DetectorsBeam DetectorsBeam Cherenkov:

p//K separationBeam TOF:

p//K separationMWPC:

Beam direction

T9 beamLarge angle tracksLarge angle tracks(inside solenoid)TPC: Tracking & PIDRPC: PID

Forward trackingForward trackingNOMAD drift chambers:

Dipole magnet:Tracking &

Momentum analysis

Forward Particle IDForward Particle IDTOF wall:PID for 0–4.5 GeV/cCherenkov:PID for 3–15 GeV/cEM calorimeter:e/ separation

Used for Forward AnalysisForward Analysis

I.Kato

Use K2K thin target (5%Use K2K thin target (5%))• To study primary p-Al interaction• To avoid absorption / secondary interactions

5%5% Al target (20mm) Al target (20mm)

Raw dataRaw data

p > 0.2 GeV/c|y | < 50 mrad

25 < |x| < 200 mrad

Pion yield: K2K thin target

K2K replica (650mm)K2K replica (650mm)

0 42 6P(GeV/c)

8 10 0 100 200-100-200x(mrad)

p-e/ misidentification background

I.Kato

Pion yieldAfter After

all correctionall correction

5% Al target p > 0.2 GeV/c|y | < 50 mrad

25 < |x| < 200 mrad

Systematics are still to be evaluated:• tracking efficiency known at 5% level• expect small effect from PID

0 42 6P(GeV/c)

8 10 0 100 200-100-200x(mrad)

Brookhaven Experiment 910Brookhaven Experiment 910E910 used a spectrometer with good acceptance and particle ID over the momentum and angular range of interest to MiniBooNE.

Particle ID from dE/dx in the TPC, threshold Čerenkov, and Time of Flight.

J.Link

E910 E910 cross section and Sanford-Wang Fit Resultscross section and Sanford-Wang Fit Results

6.4 GeV/c 12.3 GeV/c

PreliminaryPreliminary

J.Link

E910 cross section and Sanford-Wang Fit ResultsE910 cross section and Sanford-Wang Fit Results

17.6 GeV/c

Preliminary

Parameter

Value

C1 262±27

C2 0.970±0.096

C3 1.3±1.2

C4 2.28±0.77

C5 1.50±0.61

C6 5.01±0.22

C7 0.0739±0.0096

C8 16.9±2.4

J.Link

( )⎟⎟⎠

⎞⎜⎜⎝

⎛−−−⎟⎟

⎠

⎞⎜⎜⎝

⎛

−−= 8

5

4

2 cosexp1

1),,( 763

1C

BCB

C

B

CB pCpC

p

pC

p

ppCppS

Comparison to Earlier DataComparison to Earlier DataThe measured π+ cross section is similar to that measured by past experiments.

The spectrum is a little softer and the flux normalization is slightly higher at 8.9 GeV/c

Still, the production spectrum is in agreement with the old fits to within errors. (>10% in total ν flux)

Current Analysis

Cho, et al., 1971

Preliminary

J.Link

Cho et al., 1971, p+Be at 12 GeV,

d/ddp at =0,2,4,6,8,10,12 deg.

Summary

• HARP pion yield (arbitrary units) for K2K thin Al target (20mm) are available for p > 0.2 GeV/c, |y | < 50 mrad, 25 < |x| < 200 mrad. Systematics are still to be evaluated.

• BNL E910 has presented a preliminary + cross section at 6.4,12.3 and 17.6 GeV. Comparison with Sanford-Wang fit and the previous measurements shows agreement at 10% or so. Some difference at forward angle and <3 GeV region exists. Systematic errors are being studied.

• K2K/MiniBOONE wait for the publication.