1 / 13

Hard diffraction in eA

Hard diffraction in eA. Cyrille Marquet RIKEN BNL Research Center. Inclusive and diffractive structure functions. e h center-of-mass energy S = ( k + P ) 2  * h center-of-mass energy W 2 = ( k - k ’+ P ) 2 photon virtuality Q 2 = - ( k - k ’) 2 > 0. k’. k. size resolution 1/Q. p.

nansen
Download Presentation

Hard diffraction in eA

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. Hard diffraction in eA Cyrille MarquetRIKEN BNL Research Center

  2. Inclusive and diffractivestructure functions

  3. eh center-of-mass energyS = (k+P)2*h center-of-mass energyW2 = (k-k’+P)2photon virtualityQ2 = - (k-k’)2 > 0 k’ k size resolution 1/Q p Deep inelastic scattering (DIS) x ~ momentum fraction of the struck parton y~ W²/S

  4. momentum transfert = (P-P’)2 < 0diffractive mass of the final stateMX2 = (P-P’+k-k’)2 k’ k p p’ Diffractive DIS when the hadron remains intact ~ momentum fraction of the struck parton with respect to the Pomeron xpom = x/ rapidity gap :  = ln(1/xpom) xpom~ momentum fraction of the Pomeron with respect to the hadron

  5. Diffractive DIS without proton tagging e p  e X Y with MY cut H1 LRG data MY < 1.6 GeV ZEUS FPC data MY < 2.3 GeV Inclusive diffraction at HERA Diffractive DIS with proton tagging e p  e X p H1 FPS data ZEUS LPS data

  6. Collinear factorizationvsdipole factorization

  7. perturbative Collinear factorization in the limit Q²   withx fixed • for inclusive DIS a = quarks, gluons • perturbative evolutionof  with Q2 : Dokshitzer-Gribov-Lipatov-Altarelli-Parisi not valid if x is too small non perturbative • for diffractive DIS another set of pdf’s, same Q² evolution

  8. Factorization with diffractive jets ? you cannot do much with the diffractive pdfs factorization does not hold for diffractive jet production at low Q² diffractive jet production in pp collisions factorization also holds for diffractive jet production at high Q² for instance at the Tevatron: predictions obtained with diffractive pdfs overestimate CDF data by a factor of about 10 a very popular approach: use collinear factorization anyway, and apply a correction factor called the rapidity gap survival probability

  9. k’ k’ k k photon virtuality Q2 = - (k-k’)2 >> QCD *p collision energy W2 = (k-k’+p)2 2 size resolution 1/Q p p p’ • diffractive DIS: diffractive mass MX2 = (k-k’+p-p’)2 xpom = x/ rapidity gap = ln(1/xpom) The QCD dipole picture in DIS in the limit x  0withQ²fixed • deep inelastic scattering (DIS) at small xBj : sensitive to values of x as small as

  10. T = 1 T << 1 contribution of the different r regions in the hard regime DIS dominated by relatively hard sizes DDIS dominated by semi-hard sizes hard diffraction is directly sensitive to the saturation region Forshaw and Shaw no good fit without saturation effects Hard diffraction and small-x physics the dipole scattering amplitudfe dipole size r

  11. Hard diffraction off nucleisome expectations

  12. following the approach of Kugeratski, Goncalves and Navarra (2006) ratio ~ 35 % from Kowalski-Teaney model plots from Tuomas Lappi The ratio F2D,A / F2 A at HERA saturation naturally explains the constant ratio

  13. scheme dependence for naive : Pb / p FRWS : Freund, Rummukainen, Weigert and Schafer ASW : Armesto, Salgado and Wiedemann The ratio F2D,A / F2 D,p following Kugeratski, Goncalves and Navarra Au / d • x dependence full : Iancu-Itakura-Munier model linear : linearized version of IIM shape and normalization influenced by saturation

More Related