NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester1 Recent Electron Scattering Results from Jefferson Laboratory S. Manly University of Rochester Department of Physics and Astronomy NUFACT ’06, Aug Irvine, California

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester2 Recent Electron Scattering Results from Jefferson Laboratory U p d a t e o n s e v e r a l e l e c t r o n s c a t t e r i n g e x p e r i m e n t s a t J e f f e r s o n L a b r e l e v a n t f o r ν p r o g r a m S. Manly University of Rochester Department of Physics and Astronomy NUFACT ’06, Aug Irvine, California

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester3 Wait a minute … we don’t care about no stinkin’ electrons! Sure you do! …   High statistics.   Control over initial energy and interaction point – gives kinematic constraints and ability to optimize detector.   Neutrino cross section can be written as a vector piece and an axial vector piece. Can get the vector piece from electron elastic electron-nucleon form factors using CVC.   Nuclear effects on final state should be similar … the eA data can constrain models used to quantify nuclear effects and resonance production in physics. e - e - JUPITER – Jlab Unified Program to Investigate nuclear Targets and Electroproduction of Resonances

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester4 N Q2Q2Q2Q2e(E)e’(E’)θ Inclusive measurements Detect e- only in final state JLab E94-110, E02-109, E04-001, E   Completed   Proton L/T separated SF’s in resonance region   Duality works, i.e., extrapolated DIS SF’s yield what is observed by averaging out the resonance structure

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester5 N Q2Q2Q2Q2e(E)e’(E’)θ Inclusive measurements Detect e- only in final state   L/T sep. SF’s on Deuterium in the resonance region and beyond (gets at the neutron)   Already much data in hand   Expect to run in April ’07 JLab E94-110, E02-109, E04-001, E <Q 2 <2 GeV 2 Q 2 <4.5 GeV 2

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester6 N Q2Q2Q2Q2e(E)e’(E’)θ Inclusive measurements Detect e- only in final state JLab E94-110, E02-109, E04-001, E   L/T sep. cross sections and SF’s on nuclei in the resonance region and cross section measurement on nuclei at low Q 2   H, D, C, Al, Fe targets   Ran in Jan ’05, preliminary results ready

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester7 Inclusive measurements Collectively these expts get at -   Proton and neutron vector form factors   Quark-hadron duality   Nuclear effects on structure functions JLab E94-110, E02-109, E04-001, E From H. Gallager in proposal for E og 10 (Q 2 ) 1og 10 (x) Neutrino structure function measurements, MINOS coverage and coverage of E06-009, these measurements help us build a cross section model in region of relevance MINOS coverage, current configuration E coverage

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester8 Shielded Detector Hut Superconducting Dipole Superconducting Quads Electron Beam SOS Target Scattering Chamber HMS Jlab Hall C Jlab Hall C Used for detections of positrons Used for detection of electrons

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester9 e - N scattering formalism Transverse virtual photon flux σ T (σ L ) is the Transverse (Longitudinal) virtual photon Cross Section Virtual photon polarization parameter M p - mass of the Proton Born Approximation V. Tvaskis N Q2Q2Q2Q2e(E)e’(E’)θ

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester10 Rosenbluth Separation   While keeping W 2 and Q 2 fixed, we plot the reduced cross-section vs ε   Linear fit yields: σ L = Slope σ L = Slope σ T = Intercept σ T = Intercept Reduced cross-section At ε =0, α F 1 At ε =1, α F 2 Diff. α F L {

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester11 Kinematic Coverage for E and E Rosenbluth Separation Data Targets: D, C, Al, Fe, and some H for crosschecks Projected final Uncertainties estimated at 1.6 % pt-pt. Rosenbluth separations possible Low Q 2 data for ν modeling Targets: H,D, C, Al Projected final Uncertainties estimated at ~3 - 8% (Much larger RCs and rates) Data in hand and being analyzed

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester12 L/T Separation Data: Targets: D, C, Al, Fe L/T Separation Data: Targets: D, C, Al, Fe Final uncertainties 1.6 % pt-pt in ε (2% normalization) Final uncertainties 1.6 % pt-pt in ε (2% normalization) L/T Separation Data: Targets: D, C, Al, Fe L/T Separation Data: Targets: D, C, Al, Fe Final uncertainties 1.6 % pt-pt in ε (2% normalization) Final uncertainties 1.6 % pt-pt in ε (2% normalization) Includes approved future running L/T Separated Structure Functions on Nuclei (JLab E02-109, E and E06-009)

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester13 Preliminary cross section results exist Deuterium: Fits to previous JLab & SLAC res. region data. Heavy targets: fits to DIS data (F 2 & R). Deuterium: Fits to previous JLab & SLAC res. region data. Heavy targets: fits to DIS data (F 2 & R).  Error bars are statistical only.  Only inelastic data shown.  Error bars are statistical only.  Only inelastic data shown.

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester14 Preliminary results at low Q 2 D resonance is quite strong in nuclei at low Q 2 !

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester15 Preliminary results at low Q 2 D resonance is quite strong in nuclei at low Q 2 ! Even for deuterium, we need better models at low Q 2

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester16 p Fe d  = 2x[1 + (1 + 4M 2 x 2 /Q 2 ) 1/2 ] Arrington, Keppel, Ent, Niculescu PRC73: (2006) Arrington, Keppel, Ent, Mammei, Niculescu PRC73: , 2006 Arrington, Keppel, Ent, Niculescu PRC73: (2006) Arrington, Keppel, Ent, Mammei, Niculescu PRC73: , 2006 Nuclear Structure Functions   N uclear structure functions follow a single curve – shallow Q 2 dependence, x-scaling.   In nuclei the averaging is nearly accomplished by Fermi motion.   No low Q 2 or L/T data.

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester17 W 2 ~ 4 GeV 2   Ran Fall 2004 in Hall C (Arrington, spokesman).   Provides precision data on nuclear SFs/ nuclear modifications in light nuclei.   Large kinematic coverage to study x and Q 2 dependences.   Check that EMC effect is the same in resonance region as in DIS.   Data will provide precision data on A-dependence of EMC effect => help distinguish models of EMC.   Ran Fall 2004 in Hall C (Arrington, spokesman).   Provides precision data on nuclear SFs/ nuclear modifications in light nuclei.   Large kinematic coverage to study x and Q 2 dependences.   Check that EMC effect is the same in resonance region as in DIS.   Data will provide precision data on A-dependence of EMC effect => help distinguish models of EMC. New data: Jlab E – EMC in light nuclei

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester18 N Q2Q2Q2Q2e(E)e’(E’)θ Exclusive measurements Detect all (most) particles in final state JLab Hall B, CLAS detector   Large acceptance   Started taking data in 1997   Wide variety of run conditions: e-/  beams, 0.5<E<6 GeV (polarized), 1,2 H, 3,4 He, 12 C, 56 Fe, etc.

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester19 CLAS: CEBAF Large Acceptance Spectrometer (Hall B)

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester20 CLAS Single Event Display   Charged particle angles 8 o -144 o   Neutral particle angles 8 o -70 o   Momentum resolution ~0.5% (charged)   Angular resolution ~0.5 mr (charged)   Identification of p,  + /  -, K + /K -, e + /e -, etc.

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester21

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester22 (SM, R. Bradford and undergrads: Dave Sher, Ian Kleckner, Jennifer Cano) Allows neutrino MC tuners to take into account nuclear effects like transparency and absorption in a brute force way. They can look at data for vector part and appropriate Q 2 only. How often do you see proton from QE event? (Affects Evis and event categorization.) How often do you lose a pion in a resonance or inelastic event? (Affects Evis and event categorization) Coherent  o production background for electron neutrinos. How often does charge exchange happen? Is there an A dependence? Examples of measurements:   Momentum distributions for protons and charged pions in 1-  and 2-  events (E, Q 2, A=H,C,Fe)   ep  ep  o  ep  + below 2  threshold    o /  + ratio as function of W and Q 2 Neutral and charged pions look different in detectors. Need to understand A dependence. The reconstructed neutrino energy is a critical quantity for neutrino expts. Tune models with CLAS measurements. Exclusive measurements for the ν program at CLAS

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester23 (SM, R. Bradford and undergrads: Dave Sher, Ian Kleckner, Jennifer Cano) Allows neutrino MC tuners to take into account nuclear effects like transparency and absorption in a brute force way. They can look at data for vector part and appropriate Q 2 only. How often do you see proton from QE event? (Affects Evis and event categorization.) How often do you lose a pion in a resonance or inelastic event? (Affects Evis and event categorization) Coherent  o production background for electron neutrinos. How often does charge exchange happen? Is there an A dependence? Examples of measurements:   Momentum distributions for protons and charged pions in 1-  and 2-  events (E, Q 2, A=H,C,Fe)   ep  ep  o  ep  + below 2  threshold    o /  + ratio as function of W and Q 2 Neutral and charged pions look different in detectors. Need to understand A dependence. The reconstructed neutrino energy is a critical quantity for neutrino expts. Tune models with CLAS measurements. Exclusive measurements for the ν program at CLAS Are we living a fantasy? We’ll see. $ limited at the moment.

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester24 hydrogen carbon W distributions Hydrogen: E=4.462 GeV Carbon: E=4.462 GeV PreliminaryPreliminary

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester25 Missing mass squared in  (1232) resonance region e-p e-pi hydrogen carbon Preliminary Preliminary Preliminary Preliminary

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester26 e + p + 0π ep+0  threshold Can we use thresholds in W to isolate topologies? Preliminary

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester27 e + p + 0π e + p + 1π ep+0  threshold ep+1  thresholdPreliminary

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester28 e + p + 0π e + p + 1π e + p + 2π ep+0  threshold ep+1  threshold ep+2  threshold Preliminary

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester29 e + p + 0π e + p + 1π e + p + 2π e + p + 3π ep+0  threshold ep+1  threshold ep+2  threshold ep+3  thresholdPreliminary

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester30 e + p + 0π e + p + 1π e + p + 2π e + p + 3π ep+0  threshold ep+1  threshold ep+2  threshold ep+3  threshold Can isolate certain topologies of charged particles in small regions of W ep  with little/no missing mass in this region of W Preliminary

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester31 Carbon oo 11 22 33 Preliminary Preliminary Preliminary Preliminary

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester32 Neutral and charged pions look different in detectors. E is a critical quantity. Tune models that can be used in expts. i.e., K2K result, E is important Oscillations No oscillations Paschos, Schienbein, Yu, hep-ph/ ANP model calculations K2K Collaboration, hep-ex/ Exclusive measurements for the ν program at CLAS

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester33 Fermi smearing and radiative corrections ~cancel  o  + acceptance differences ~cancel Fermi smearing and radiative corrections ~cancel ANP model preliminary result: private communication from I. Schienbein, E Paschos, J. Yu

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester34 Fermi smearing and radiative corrections ~cancel  o  + acceptance differences ~cancel Fermi smearing and radiative corrections ~cancel Invariant mass of Reconstructed pizeros Can do direct detection of π o ’s Preliminary Double ratio sensitive to slight variations in detector behavior between the C and H runs … stay tuned.

NUFACT06, Irvine, CA August 25, 2006 S. Manly, University of Rochester35Conclusions A very rich program of inclusive eA experiments underway at JLab providing information on low Q 2 cross section as well as nuclear effects and the validity of duality in the resonance region. Many useful measurements already done. Vast amount of exclusive data available from CLAS. Effort underway to do exclusive analyses geared toward neutrino needs. Thanks for help from E. Christy, C. Keppel, V. Tvaskis, J. Steinman.