arie bodek, univ. of rochester0 -------quasielastic scattering in minerva ------- a. bodek, h. budd...

Arie Bodek, Univ. of Rochester 1

-------Quasielastic Scattering in MINERvA -------

A. Bodek, H. Budd - Rochester will get Steve Manly -Rochester and

Tony Man -Tufts also involved

Clear example of Bridging Physics between Jlab and MINERva at Fermilab

Physics:

• Quasielastic cross sections for neutrino oscillations - Dominated by low Q2, Axial Mass, Pauli exclusion, low Q2 modification of form factors in nuclear medium, Nuclear Effects/Final state interactions and Identification of the quasielastic channel, misidentification of resonances as quasielastic etc. (important for JHF to SuperK)

• Measurement of axial form factor at high Q2. Is it the dipole form, or another form - a new line of investigation only possible by the high statistics and precision of Minerva

For both, need to do a comparison of electron and neutrino scattering - (S. Manly - electron scattering Jlab Hall B CLAS data - e.g. Final states in quasielastic).Also use electron data to extrapolate Carbon to Oxygen and cancel as well as understand, nuclear effects.


JHF region 0.7 GeV

FNAL region 3 GeV

JHF region 0.7 GeV

Arie Bodek, Univ. of Rochester 3JHF region

0.7 GeV

FNAL region

3 GeV


We are currently investigating

• Effect of Pauli suppression with Bodek/Ritchie High momentum tail

• Use more sophisticated spectral functions for nuclear effects

• Need to study effect of off-shell definitions of form factors

• Effect of suggested modifications of form factors inside nucleus

Strickman says that form factor modification may be true at low Q2 but not true for Q2 gt. 1 GeV2 (as indicated by Jlab data).

• Investigate how the neutrino experiments select quasielastic events (is it in the experiment)

• Need to measure both Q2 distribution and Cross sections


Start with: Quasielastic: C.H. Llewellyn Smith (SLAC).Phys.Rept.3:261,1972

Vector form factors

From electron

scattering

Via CVC

Axial form factor fromNeutrino experiments

Neutrino experiments useDipole form factors with Gen=0 -Because this is what was put in the LS paper (not exactly correct)

Vector

VectorAxial

Updated recentlyBy Bodek, Budd andArrington 2003


What does axial form factor Fa do between 1 and 3 GeV2 ????

Budd, Bodek, Arrington BBA-2003 Form Factor Fits to SLAC/JLAB data. Vector Nucleon form factors display deviations from dipole. Controversy on Gep high Q2


K2K Near detectordata on Water wasFit with wrong Vector Form factors. NewBBA2003 form factorsand updated M_A have asignificant effect on Neutrino oscillations Results.


Updating Neutrino Axial Form Factors:-->

Use new BBA-2003 Precise Vector Form Factors as input to neutrino data. With BBA-2003 Form Factors, Axial Vector M_A=1.00. However, no information on Axial form factor for Q2>1 GeV2.

Future: Very High Statistics neutrino data will be available on Carbon. Need precise vector form factors, as modified in Carbon (including effect of experimental cuts)

Can measure F_A(Q2)/ GM_V(Q2) at High Q2 - By combining Jlab and MINERvA data

Quasielastic

Old Bubble Chamber

Data on D2. (Steve Manly was

A member of this collaboration

(as a PhD Thesis student)

Arie Bodek, Univ. of Rochester 10Arie Bodek, Univ. of Rochester 17

Baker 1981 D2

Q2<0.3 Region, Interest

1. Determine Ma=radius of axial proton

2. Compare to Ma from pion electroproduction

3. Determine quaielastic cross section where mostof the events are - for neutrino oscillation in the1 GeV region , e.g. K2K,JHF MiniBoone.

4. Sensitive to both Pauli Exclusion and final stateID if a nuclear target is used, e.g. Carbon, Water.Lose Quasielastic events, or misID resonanceevents. -> - Need to use Jlab Hall B data on D2, Cand Fe - Manly Analysis proposal

5. Low recoil proton momentum P=Sqrt(Q2)

Q2 > 1 GeV2 Region, Interest

1. Determine deviations from Dipoleform factors is it like Gep or Gmp .

2. Not sensitive to Paul Exclusion,but sensitive to final state ID. -> -Need to use Jlab Hall B data on D2,C and Fe - Manly analysisproposal

3. Higher recoil proton momentumP=Sqrt(Q2)

Pauli effect on C12, Q2<0.3 GeV2

Measure F_A(Q2)/GM_V(Q2) by comparing neutrinoAnd electron e-e’-p data on Carbon with 1 Million events


Precise measurement of Axial Form factor of the Nucleon can only be done using a combined analysis (with the same cuts) of a sample of e-e’-p data from electron scattering at Jlab (on Carbon) with the Corresponding - ’ p data from neutrino scattering On Carbon and using same cuts (on final state proton etc). (measure F_A at high Q2 for first time).

Since future high statistics neutrino data will only be done with nuclear targets (e.g. scintillator), Nuclear Effects can both be studied, as well as cancelled by performing a combined analysis of these two data sets.

Collaborate with a parallel program in Hall B (Manly): Produce well understood DSTs of e-e’ X on Carbon that can be used in a combined analysis with neutrino data. Start with quasielastic, and continue on to resonances, and DIS. In the process, also do physics such as nuclear transparency, modification of resonance and DIS final states in nuclei, etc.


F_A/FA_Dipole (M_a=1.0) from Q2=0 to Q2=3

(normalized to 1 at Q2=0. BBA03 get best fit Ma=1.0 GeV2)

Dipole Ma=1.1

Ma=1.0 is line at 1.0

Sehgal prediction

Dipole Ma=0.9

What does axial form factor Fa do between 0 and 3 GeV2 ????

Lalit Sehgal 1979 EPS Conference on High Energy Physics in Geneva (Proc,Vol.1,p.98,published byCERN). F_A / G_MV should be taken to be the ratio of the A_1 and rho poles (not dipoles),G_MV itself being taken from electron scattering.Explicitly,

F_A/G_M=(1-q^2/M_rho^2)/(1-q^2/M_A1^2), where M_rho=0.77GeV,M_A1~sqrt(2)*M_rhoGeV.

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1 2 3 4 5 6 7 8 9 10 11 12 13

Series1

Series2

Series3


F_A/F_A_Dipole (M_a=1.0) from Q2=0 to Q2=3 (normalized)

What does axial form factor Ga do between 0 and 3 GeV2 ????

Dipole Ma=1.2

Ma=1.0 is 1.0

Sehgal prediction

Dipole Ma=0.8

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1 2 3 4 5 6 7 8 9 10 11 12 13

Series1

Series2

Series3


Q2<0.3 Region, Interest

1. Determine Ma=radius of axial proton

2. Compare to Ma from pion electroproduction

3. Determine quaielastic cross section where most of the events are - for neutrino oscillation in the 1 GeV region , e.g. K2K,JHF MiniBoone.

4. Sensitive to both Pauli Exclusion and final state ID if a nuclear target is used, e.g. Carbon, Water. Lose Quasielastic events, or misID resonance events. -> - Need to use Jlab Hall B data on D2, C and Fe - Manly Analysis proposal

5. Low recoil proton momentum P=Sqrt(Q2)

Q2 > 1 GeV2 Region, Interest

1. Determine deviations from Dipole form factors is it like Gep or Gmp .

2. Not sensitive to Paul Exclusion, but sensitive to final state ID. -> - Need to use Jlab Hall B data on D2, C and Fe - Manly analysis proposal

3. Higher recoil proton momentum P=Sqrt(Q2)


0.5 GeV P = 15 cm of scintillator = 120 MeV energy

Versus 1 mip = 2 MeV/cm. Get 60 mips

For Q2=0.110 GeV2, q3=P=0.330 GeV

Proton kinetic energy = P**2/2M = 55 MeV

Range about 5 cm - Note nuclear binding about 30 MeV

Back of envelope estimates - needs to be done more quantitatively


Note: all particles at a given angle must have energies lower than a quasielastic muon


Case of magnetized Steel MINERVAB-H Curve for steel can be found at http://www-fmi.fnal.gov/fmiinternal/MI_Notes_Pages/MI-0127.pdfwhich has been backed up to http://www.pas.rochester.edu/~bodek/minerva/MI-0127.pdf

Table 3 page 12 for Armco steel show that for H=10, B=10 Kgauss (B=1 T, or mu-1000). Pretty much around 1000 for lower H. However to get to saturated iron is hard. For H=30, B-15 and for H-60 B=20.5. So need a factor of 6 more current to go from B=10 Kgauss to B=20 Kgauss (below H=10 it is linear).

Scaling from CCFR, which has B=1.6 T and L=4.8 meter and resolution of 10%. One gets momentum resolution (which will only be used for sign) of

Sigma = (16%/ B(Tesla) * Sqrt [4.8/L(meters) ] Pt kick = 2.4 GeV/c * (B/1.6 T) *(L meter/4.8m)

so for 1.2 iron at 1 T we get sigma of 16% times 2 or 32%. (PT KICK OF 0.44 GeV)Factor of 2 Better if we use 2 T (see below) which requires factor of 10 more current Energy resolution from range is just how well you can determine range (the more scintillator sampling, the better range is determined).

What kind of current do we need.Lab E has 4 coils. 12 turns 1200 amp each. total NI=48x1200 Amp Get 1.9 T at 1 foot and 1.55 T at the edge. 2.4 GeV Pt kick. However, it does not have quality magnet iron steel.

For a square rod going around Minerva of L=4x4 meter so total path of magnetic field is 16 meters (most outerDesign, inner path is L=2*4=8 meter H = 4*Pi* (10**-3) N I /16 m in Orested

Need to get H above 10, so running with 48 coils at between 300 and 500 Amps gives B=12 to 14 Kgauss(see spreadsheet).


LTV

Not optical


Armco

better


Active target 2mx2m

Picture frame.

EM Cal : 8 1.25 cm Fe plates followed by 8 1.25 cm scintillators

Had/Muon range detector 8 10 cm followed by 8 1.25 cm scintilltors

Total = 12,.5 cm Fe + 80 Cm Fe = 92.5 cm Fe

and 16x 1.25 = 20 cm scintillator


Armco

Steel

Res with 0.92 m FeI 300 N 48 0.92

angleL H B 90 45 30 Pt8 23 13.6 0.27 0.23 0.19 0.39

12 15 12.1 0.30 0.25 0.21 0.35

I 500 N 48

L H B8 38 15.8 0.23 0.19 0.16 0.45

12 25 14.3 0.26 0.21 0.18 0.41

I 150 N 48

L H B8 11 10.5 0.35 0.29 0.25 0.30

12 8 9 0.41 0.34 0.29 0.26


0 3 14.3 015 2.71 12.9 0.630 2.10 10.0 1.745 1.55 7.4 2.760 1.15 5.5 3.590 0.71 3.4 4.3

135 0.46 2.2 4.8180 0.41 1.9 4.9

0 10.00 47.7 0.015 7.34 35.0 5.030 4.12 19.6 11.045 2.43 11.6 14.260 1.58 7.5 15.890 0.86 4.1 17.2

135 0.52 2.5 17.8180 0.45 2.1 17.9

Theta E' range m transverse Q2

arie bodek, univ. of rochester0 -------quasielastic scattering in minerva ------- a. bodek, h. budd...

Documents

neutrino axial form

dipole form factors

precise vector form

vector nucleon form

wrong vector form factors

arie bodek

form factor modification

new bba2003 form factors