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Mila Panduroviċ Vinča Institute of Nuclear Sciences,Srbija

Deep inside a proton - structure functions F2 for heavy flavors. Mila Panduroviċ Vinča Institute of Nuclear Sciences,Srbija. Q 2. The key to inner life of proton is so-called structure function. Q 2. Back in the old days ….

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Mila Panduroviċ Vinča Institute of Nuclear Sciences,Srbija

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  1. Deep inside a proton - structure functions F2 for heavy flavors Mila Panduroviċ Vinča Institute of Nuclear Sciences,Srbija

  2. Q2 The key to inner life of proton is so-called structure function Q2 Back in the old days … So in order to see a most intimate life insideproton (heavy flavors) one should consider shooting the biggest available arrow

  3. Q2 X= 2 p·q p·q p·k Y= Charged current Neutral current High Energy eP collisions Characteristic variables Virtuality Bjorken scaling variable Inelasticity Q2= - q2 = - (k-k’)2 Photoproduction (p) Q2 < 1 GeV2 Low Q2 DIS : 1< Q2 < 100 GeV2 High Q2 DIS : Q2 > 100 GeV2 Kinematic regimes

  4. e’ e P parton Quark parton model (QPM) • If the resolution with which the proton is probed is sufficiently fine ( large enough Q2 ) hadrons are viewed as being composed of a number of point-like constituents-partons If |p|2»mp2 QPM interprets Deep Inelastic Scattering as the elastic scattering of a e- (e+) from a single quark The eP cross section is an incoherent sum of - individual eqi scattering cross sections times the probability -fi(x) that quark qi is carrying fraction x of proton’s momentum

  5. [ y2xF1 + (1-y)F2] = d2σNC dxdQ2 Deep Inelastic Scattering - DIS 2πα2 xQ4 F2(x)= ei2·x·[qi(x)+ qi(x)] i Inclusive DIS cross section Inclusive NC DIS cross section of ep → eX depends on two independent kinematic variables (chosen to be) x and Q2 F2(x)=2 ·x · F1(x) F1(x),F2(x)– proton structure functions are giving the probability fi(x)=qi(x)dx of finding a quark carrying fraction x of a proton’s momentum (weighted by the electric charge of a quark)

  6. What proton is made of …

  7. Goal of the analysis Measurement of the charm and beauty content in both low and high Q2 ePneutral current interactions andcalculation ofcharm and beauty contributionsF2cc and F2bb to the proton structure function For this purpose the property of long lifetime of charm and beauty hadrons is exploited

  8. Inclusive DCA Method DCA Method is based on lifetime information of heavyhadrons –impact parametersδ~DCAare differentfor heavy and light quarks DCA - Distance of Closest Approach

  9. H1CentralTrack H1CentralTrack H1Selection H1Vertex H1SVFit ?  ! H1CalcJet H1CalcVertex Tools - h1oo

  10. HERA I Data HERA II Data CJC tracks CST Hits CJC tracks CST Hits CJC- CST track fit CJC- CST track fit FST tracks CST Tracks CST Tracks Data and MC DATA MONTE CARLO uds DJANGO cc, bb RAPGAP, CASCADE p  X PHOJET All MC event samples are passed through H1 detector simulation program

  11. δ σ(δ) S= Signed impact parameter Significance Error on DCA Quark flavour separation S1,S2,S3- significance of tracks with highest, second highest and third highestabsolute significance To reduce the uncertainty due to resolution and suppress contribution from light quarks will be using “subtracted” significance distributions ΔS=S+- S-

  12. Total MC uds c b - Data Adding this to CV SORRY NO CAN DO ! H1PLOTTER Plot anything please !!! Very much Please The nicest Please

  13. Significance distributions

  14. d2σNC dxdQ2  Pc · NcMCgen Pc · NcMCgen + Pb · NbMCgen+Pl · NlMCgen  cc(x,Q2)= NC(x,Q2) BCC  xQ4 2·π·α [1+(1+y)2] NC(x,Q2)= y2 1+(1+y)2 FLcc  F2cc=cc+ Fitting Using the least squares simultaneous fit of the subtracted S1,S2 and S3 we are obtaining the scaling factors Pc, Pb and Pl of the number of heavy and light quarks The obtained fractions of heavy quarks are used to calculate the reduced cross section for interaction of heavy quarks c(b) Using this we obtain the structure functions for c ( or b) 

  15. LHC Summary Structure functions are inheritance which HERA is giving us for the future experiments As we are going to “feed” that to LHC...  I hope that is going to be theexact meal or …something or someone else is going to be served … Coach : Ivanka Božoviċ-Jelisavčiċ advising: Paul Thompson, Tatsiana Klimkovich … M. Panduroviċ, Vinča Institute of Nuclear Sciences, X talks, 18-19 october, 2007

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