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

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

3. High Energy eP collisions Neutral current Charged current Characteristic variables Virtuality Bjorken scaling variable Inelasticity Photoproduction (  p) Q 2 < 1 GeV 2 Low Q 2 DIS : 1< Q 2 < 100 GeV 2 High Q 2 DIS : Q 2 > 100 GeV 2 Kinematic regimes 2 p·q X= Q2Q2 Y= p·q p·k Q 2 = - q 2 = - (k-k’) 2

4. Quark parton model (QPM) If the resolution with which the proton is probed is sufficiently fine ( large enough Q 2 ) hadrons are viewed as being composed of a number of point-like constituents-partons If |p| 2 »m p 2 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 eq i scattering cross sections times the probability -f i (x) that quark q i is carrying fraction x of proton’s momentum e P parton e’

5. Inclusive DIS cross section Inclusive NC DIS cross section of ep → eX depends on two independent kinematic variables (chosen to be) x and Q 2 2πα 2 xQ 4 [ y 2 xF 1 + (1-y)F 2 ] d 2 σ NC dxdQ 2 = F 1 (x),F 2 (x) – proton structure functions are giving the probability f i (x)=q i (x)dx of finding a quark carrying fraction x of a proton’s momentum (weighted by the electric charge of a quark) Deep Inelastic Scattering - DIS F 2 (x)=2 ·x · F 1 (x) F 2 (x)=  e i 2 · x·[q i (x)+ q i (x)] i

6. What proton is made of …

7. Goal of the analysis Measurement of the charm and beauty content in both low and high Q 2 eP neutral current interactions and calculation of charm and beauty contributions F 2 cc and F 2 bb 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 heavy hadrons – impact parameters δ~DCA are different for heavy and light quarks DCA - Distance of Closest Approach

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

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

11. Quark flavour separation S 1, S 2,S 3 - significance of tracks with highest, second highest and third highest absolute significance To reduce the uncertainty due to resolution and suppress contribution from light quarks will be using “subtracted” significance distributions ΔS=S + - S - Signed impact parameter Significance Error on DCA S= δ σ(δ)

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

13. Significance distributions

14. Fitting Using the least squares simultaneous fit of the subtracted S 1, S 2 and S 3 we are obtaining the scaling factors P c, P b and P l 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)  F 2 cc =  cc + y 2 1+(1+y) 2 F L cc  Using this we obtain the structure functions for c ( or b)   NC (x,Q 2 )= xQ 4 2·π·α [1+(1+y) 2 ] d 2 σ NC dxdQ 2   cc (x,Q 2 )=  NC ( x,Q2 ) P c · N c MCgen P c · N c MCgen + P b · N b MCgen +P l · N l MCgen  BCC 

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