E.C. AschenauerEIC INT Program, Seattle Week 51

Precision Measurement of F L with the EIC E.C. Aschenauer EIC INT Program, Seattle Week 52 F L ~  s G(x,Q 2 ): the most “direct” way to G(x,Q 2 ) F L needs various √s  longer program In order to extract F L one needs at least two measurements of the inclusive cross section with a “wide” span in inelasticity parameter y (Q 2 =sxy) Coverage in x & Q 2 for inclusive cross section measurements Plots for 4 GeV electrons on 50 – 250 GeV protons

Measuring F L with the EIC E.C. Aschenauer EIC INT Program, Seattle Week 53 Conclusion from this study  Dominated by sys. uncertainties  gives max. luminosity  gives max. luminosity  here: 4fb -1 / A  here: 4fb -1 / A  Depending on x & Q 2 might be able to take a hit in luminosity able to take a hit in luminosity  need to include  need to include detector effects detector effects Lets get a feeling for systematic uncertainties 1% energy-to-energy normalization F L for fixed electron energy (4GeV) and proton energies: 50, 70, 100, 250 GeV Luminosity: 4fb -1 each setting

Measure g A (x) impact parameter dependent E.C. Aschenauer 4 Stringent requirements on:  Momentum resolution  t resolution and range EIC INT Program, Seattle Week 5 A. Caldwell, H. Kowalski Phys.Rev.C81:025203,2010 Radiative Correction will impact them

Some Info on RadCors  Inclusive cross section   tot =  ela +  qela +  inel +  v for all parts photons can be radiated from the incoming and outgoing lepton, high Z-material Compton peak. radiation is proportional to Z 2 of target, like bremsstrahlung radiation is proportional to 1/m 2 of radiating particle  elastic:  quasi-elastic: scattering on proton of nuclei proton stays intact proton stays intact nuclei breaks up nuclei breaks up  two photon exchange? Interference terms? E.C. Aschenauer EIC INT Program, Seattle Week 55 initial final vacuum loops

Why are RadCor important?  Modify kinematics  Q 2 :  initial state: E’ beam = E beam – E  photon goes along the beam line  final state: E’ out = E out – E  photon goes somewhere in Calo  RadCor and detector smearing don’t factorize  need to have RadCor implemented in MC to unfold effects on kinematics  unfolding in bins N true =N meas -N bckg E.C. Aschenauer EIC INT Program, Seattle Week 56 events smeared into acceptance

RadCor and smearing unfolding in MC E.C. Aschenauer EIC INT Program, Seattle Week 57 generate observed kinematics x meas, Q 2 meas Radiative Correction Code photon radiated no photon radiated x true =x meas, Q 2 true =Q 2 meas calculate x true, Q 2 true hand kinematics to generator (lepto, pythia,..) What subprocess is generated is regulated by phase space Hand particles to GEANT

What do we know?  A lot of radiative correction codes for proton  much less existing for eA all experiments apart from HERMES had  -beams suppressed radiation HERMES uses modified version of RADGEN (hep-ph/ v1) Radiative corrections to deep inelastic scattering on heavy nuclei at HERA I. Akushevich and H. Spiesberger I. Akushevich and H. Spiesberger QED radiative processes in electron-heavy ion collisions at HERA K. Kurek K. Kurek E.C. Aschenauer EIC INT Program, Seattle Week 58

What do we know? E.C. Aschenauer EIC INT Program, Seattle Week 59  < x < and 27.5 GeV x 410 GeV  solid: inelastic rad. corrections  dashed: inelastic, quasi-elastic and elastic rad. corrections Huge effects at high y PbSCHeD

What do we know? E.C. Aschenauer EIC INT Program, Seattle Week 510 Compton peak relevant if momentum transfer to nucleus very small effect of nuclear form factor included

What do we know? E.C. Aschenauer EIC INT Program, Seattle Week 511  Two photon exchange two photon exchange only important for very heavy nuclei

Can we suppress things?  elastic/quasi-elastic part: require some hadrons in detector  solid line: inelastic contribution  dashed line: after cuts E  > 10 GeV  E-p z from hadronic state is smaller E.C. Aschenauer EIC INT Program, Seattle Week 512 Need a code, which puts all together to make full calculations need to test analysis strategies to suppress rad. corrections SCHeD

 Djangoh  mainz.de/~hspiesb/djangoh/djangoh.html is compiled at BNL and running mainz.de/~hspiesb/djangoh/djangoh.html mainz.de/~hspiesb/djangoh/djangoh.html  eA part is included need to do more studies  HERACLES can be interfaced with other MC codes  HERMES code (RADGEN + eA version of lepto) is installed at BNL and close to run. No nuclear effects are included.  can compare results between eA-RADGEN with HERACLES  can nPDFs be included?  Hubert Spiesberger is coming to INT next week, juhu E.C. Aschenauer EIC INT Program, Seattle Week 513 and Summary

E.C. Aschenauer EIC INT Program, Seattle Week 514 BACKUP