1 / 27

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

-------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:

ulf
Download Presentation

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

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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 scatteringJlab Hall B CLAS data- e.g. Final statesin quasielastic).Also use electron data to extrapolate Carbon to Oxygen and cancel as well as understand, nuclear effects. Arie Bodek, Univ. of Rochester

  2. JHF region 0.7 GeV FNAL region 3 GeV Arie Bodek, Univ. of Rochester JHF region 0.7 GeV

  3. FNAL region 3 GeV JHF region 0.7 GeV Arie Bodek, Univ. of Rochester

  4. 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 Arie Bodek, Univ. of Rochester

  5. Arie Bodek, Univ. of Rochester

  6. Start with: Quasielastic: C.H. Llewellyn Smith (SLAC).Phys.Rept.3:261,1972 Updated recently By Bodek, Budd and Arrington 2003 Axial Vector Vector form factors From electron scattering Via CVC Vector Neutrino experiments use Dipole form factors with Gen=0 -Because this is what was put in the LS paper (not exactly correct) Arie Bodek, Univ. of Rochester Axial form factor from Neutrino experiments

  7. 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 What does axial form factor Fa do between 1 and 3 GeV2 ???? Arie Bodek, Univ. of Rochester

  8. K2K Near detector data on Water was Fit with wrong Vector Form factors. New BBA2003 form factors and updated M_A have a significant effect on Neutrino oscillations Results. Arie Bodek, Univ. of Rochester

  9. 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

  10. Measure F_A(Q2)/GM_V(Q2) by comparing neutrino And electron e-e’-p data on Carbon with 1 Million events Arie Bodek, Univ. of Rochester

  11. 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 n - m’- 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. Arie Bodek, Univ. of Rochester

  12. 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) What does axial form factor Fa do between 0 and 3 GeV2 ???? Dipole Ma=1.1 Ma=1.0 is line at 1.0 Sehgal prediction Dipole Ma=0.9 Lalit Sehgal 1979 EPS Conference on High Energy Physics in Geneva (Proc,Vol.1,p.98,published by CERN). 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. Arie Bodek, Univ. of Rochester

  13. 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 Arie Bodek, Univ. of Rochester

  14. Q2<0.3 Region, Interest Determine Ma=radius of axial proton Compare to Ma from pion electroproduction Determine quaielastic cross section where most of the events are - for neutrino oscillation in the 1 GeV region , e.g. K2K,JHF MiniBoone. 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 Low recoil proton momentum P=Sqrt(Q2) Q2 > 1 GeV2 Region, Interest Determine deviations from Dipole form factors is it like Gep or Gmp . 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 Higher recoil proton momentum P=Sqrt(Q2) Arie Bodek, Univ. of Rochester

  15. Back of envelope estimates - needs to be done more quantitatively 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 Arie Bodek, Univ. of Rochester

  16. Note: all particles at a given angle must have energies lower than a quasielastic muon Arie Bodek, Univ. of Rochester

  17. Case of magnetized Steel MINERVA B-H Curve for steel can be found at http://www-fmi.fnal.gov/fmiinternal/MI_Notes_Pages/MI-0127.pdf which 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 outer Design, 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). Arie Bodek, Univ. of Rochester

  18. Arie Bodek, Univ. of Rochester

  19. Arie Bodek, Univ. of Rochester

  20. Arie Bodek, Univ. of Rochester

  21. Arie Bodek, Univ. of Rochester

  22. Arie Bodek, Univ. of Rochester

  23. LTV Not optical Arie Bodek, Univ. of Rochester

  24. Armco better Arie Bodek, Univ. of Rochester

  25. 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 Arie Bodek, Univ. of Rochester

  26. Armco Steel Arie Bodek, Univ. of Rochester

  27. Arie Bodek, Univ. of Rochester

More Related