Status of 2D hadron Status of 2D hadron attenuation paperattenuation paper

Z. Akopov for DC_73Z. Akopov for DC_73

Motivation/ResultsMotivation/Results

In addition to Long paper, performed In addition to Long paper, performed 2D analysis for Neon, Krypton and 2D analysis for Neon, Krypton and Xenon for all charged hadrons Xenon for all charged hadrons separately:separately:

Nu, Q2, pt2 and Lc in 3 z-rangesNu, Q2, pt2 and Lc in 3 z-ranges Z,Q2,pt2 and Lc in 3 nu-rangesZ,Q2,pt2 and Lc in 3 nu-ranges Nu,z,Q2 and Lc in 2 pt2-rangesNu,z,Q2 and Lc in 2 pt2-ranges 1D Lc dependence1D Lc dependence

Results overviewResults overview

Normally Normally attenuation goes to attenuation goes to 1; for proton in 1; for proton in heavier targets – heavier targets – different behavior – different behavior – slope changes.slope changes.

Should be Should be reflected/accounted reflected/accounted for in model for in model calculationscalculations

Results overviewResults overview

Tendency seen for Tendency seen for pions, remains for pions, remains for K,pK,p

At leading z, little to At leading z, little to no broadeningno broadening

Results overviewResults overview

Nu-dependencyNu-dependency As opposed to As opposed to

pions, amplification pions, amplification at high pt2 on at high pt2 on heavier targetsheavier targets

Rescattering, more Rescattering, more protons.protons.

Models have to Models have to explainexplain

Results overviewResults overview

When divide in z-When divide in z-ranges, no more ranges, no more scaling for proton!scaling for proton!

Slopes differentSlopes different

Results overviewResults overview

Anti-protons – Anti-protons – similar to pions and similar to pions and co.co.

Results overviewResults overview

Different hN x-Different hN x-section for K+/K- section for K+/K- and p/anti-p, well and p/anti-p, well reflectedreflected

Otherwise, for each Otherwise, for each charge scaling charge scaling remains.remains.

Questions imposed to paperQuestions imposed to paper Are we able to explain the features of Are we able to explain the features of

2d-dependencies just based on 2d-dependencies just based on published 1d data?published 1d data?

What can be achieved using the 2d-What can be achieved using the 2d-data for all charged hadrons and how data for all charged hadrons and how useful is that for theory?useful is that for theory?

ArgumentsArguments Clear difference between super-ratio for Clear difference between super-ratio for

positive/negative hadrons, i.e. kaons and positive/negative hadrons, i.e. kaons and protonsprotons

Lc dependence data for various kinematic Lc dependence data for various kinematic ranges, gives solid experimental proof of ranges, gives solid experimental proof of different production mechanisms of different production mechanisms of proton as opposed to other hadronsproton as opposed to other hadrons

Important: such behavior is not possible Important: such behavior is not possible to predict based on the published data: to predict based on the published data: interpretation of these new data should interpretation of these new data should motivate new approaches to theoretical motivate new approaches to theoretical threatment of hadronizationthreatment of hadronization

ConclusionConclusion

HERMES possesses new set of results HERMES possesses new set of results that are clearly needed on the that are clearly needed on the market.market.

Either separate paper to present Either separate paper to present these results, or an addendum to the these results, or an addendum to the Long NA paper.Long NA paper.