Oleg Samoylov (JINR, Dubna) @ AYSS’12 conf., Feb. 6-11, 2012 Precise measurement of Charm Dimuon production cross-section in νN interactions and its various applications Oleg Samoylov (JINR, Dubna) @ AYSS’12 conf., Feb. 6-11, 2012

Motivation of the Charm Dimuons Charge current (CC) Neutral current (NC) qu (ν) qd (ℓ) f f' g g / Cos θW W+ Z0 NuTeV analysis Sin2θW = 1 − MW2/MZ2 = 0.2277 ± 0.0013 (stat.) ± 0.0009 (syst.) Rν = σνNC / σνCC = 0.3916 ± 0.0013 (SM 0.3950) Rν = σνNC / σνCC = 0.4050 ± 0.0027 (SM 0.4066) Charm dimuons in NOMAD Oleg Samoylov (JINR)

Motivation of the Charm Dimuons NuTeV for the NOMAD Roberto Petti Charm dimuons in NOMAD Oleg Samoylov (JINR)

A direct probe of the Strange sea Proton structure is defined by Parton Distribution Functions (PDF’s) of quarks q(x) and gluons g(x) νµN → µ−µ+ X νµs → µ−c → µ−µ+ X Charm dimuons in NOMAD Oleg Samoylov (JINR)

Available charm dimuon data νµN → µ−µ+ X ⇒ νµs → µ−c → µ−µ+ X Experiment Pubication Charm dimuons Neutrino Energy, GeV CDHS Jun.1982 9 922 30-250 (20) CHARM II Oct. 1999 3 100 35-290 (24) NOMAD Jul. 2000 2 714 14-300 (27) NuTeV Feb. 2001 5 102 20-400 (157.8) CCFR 5 030 30-600 (150) CHORUS Apr. 2008 8 910 15-240 (27) Strange sea PDF s(x) based on approx. 10 000 events only Charm dimuons in NOMAD Oleg Samoylov (JINR)

Neutrino induced charm dimuons ν-induced charm dimuon production Dc = Σ fh Dch, Bμ = Σ fh B (h → μ+ X), h = D0, D+, Ds+, Λ+ Charm production in (anti)neutrino DIS provides a clean and direct access to s(x) |Vcs|2=0.95 |Vcs|2=0.05 Charm dimuons in NOMAD Oleg Samoylov (JINR)

NOMAD experiment at CERN SPS 1995-1998 Front Calorimeter (FCAL) Muon neutrino beam NIM A 515 (2003) 800-828 Drift Chambers (DCH) NIM A 404 (1998) 96-128 1. Largest samples of neutrino interactions currently available: - 20 M events with Iron in Front Calorimeter (50 k dimuons) - 2.5 M events with Carbon in Drift Chambers 2. Resolution for the vertexes: in Drift Chambers 0.1 ÷ 0.25 cm and in Front Calorimeter 0.6 ÷ 1.0 cm 3. Excellent reconstruction quality of individual (charged) tracks ∆p/p=3.5%, ε=95% 4. Good calorimetry: for ECAL ∆E/E=3.2%/E[GeV], for FCAL and HCAL ∆E/E=104%/E[GeV] Charm dimuons in NOMAD Oleg Samoylov (JINR)

Reconstruction of the dimuon events Eν = Eµ− + Eµ+ + Ehad Event information Eν = 81.4 GeV Eµ− = 32.6 GeV Eµ+ = 19.0 GeV Mµµ = 0.945 GeV Q2 = 3.26 GeV2 W2 = 89.4 GeV2 Background Signature Stat. Eff., % νμ CC 8 759 065 65.8 μ-μ+ 20 480 22.5 μ-μ- 7 150 Charm dimuon Charm dimuon exp. DATA and Bg. subtraction: Charm dimuons in NOMAD Oleg Samoylov (JINR)

Relevance of the NOMAD dimuon data νµN → µ−µ+ X ⇒ νµs → µ−c → µ−µ+ X Experiment Pubication Charm dimuons Neutrino Energy, GeV CDHS Jun.1982 9 922 30-250 (20) CHARM II Oct. 1999 3 100 35-290 (24) NOMAD Jul. 2000 2 714 14-300 (27) NuTeV Feb. 2001 5 102 20-400 (157.8) CCFR 5 030 30-600 (150) CHORUS Apr. 2008 8 910 15-240 (27) 2011 15 340 6-300 (27) The NOMAD has the largest sample of ν-induced charm dimuons The neutrino energies closest to the charm production threshold Charm dimuons in NOMAD Oleg Samoylov (JINR)

Charm dimuon X-section measurement Measure RATIO of cross-sections to reduce systematics Rµµ ≡ σµµ /σcc ≃ Nµµ /Ncc (x); x = Eν , xBj , √s Require leading µ− and Q2 ≥ 1 GeV2 ∫ σµµ φ dx dy dEν = 5.15 ± 0.05 × 10−3 νµ CC Total systematic uncertainty (17 different sources) ~ 2% Agreement with model calculation based upon global PDF fit with NuTeV+CCFR dimuon data only Charm dimuons in NOMAD Oleg Samoylov (JINR)

Sensitivity to the Strange sea Add NOMAD σµµ /σcc to global PDF fit with NuTeV and CCFR dimuon data S. Alekhin, R.Petti Consistency of central values Reduction of s(x) uncertainty by a factor 2 down to 3% Charm dimuons in NOMAD Oleg Samoylov (JINR)

Strange sea and c-quark parameters Charm quark mass and strange sea supression factor Experiments mc (mc), GeV κs E531 + NuTeV + CCFR 1.010 ±0.095 0.62 ±0.005 E531 + NOMAD 1.058 ±0.059 0.63 ±0.004 E531 + NuTeV + CCFR + NOMAD 1.070 ±0.067 0.61 ±0.002 Charm dimuons in NOMAD Oleg Samoylov (JINR)

Strange sea and c-quark parameters Charm fragmentation D(z, ε) in Collins-Spiller parametrization Experiments ε E531 0.169 ±0.036 NOMAD 0.165 +0.035 / -0.026 E531 + NOMAD 0.165 ±0.025 Semileptonic branching ratio Bµ(Eν) = a/(1 + b/Eν) Experiments a b, GeV E531 0.094 ±0.010 6.6 ±3.9 E531 + NuTeV + CCFR 0.086 ±0.006 4.1 ±2.5 E531 + NOMAD 0.094 ±0.004 6.0 ±1.6 E531 + NuTeV + CCFR + NOMAD 0.094 ±0.003 5.6 ±1.4 Charm dimuons in NOMAD Oleg Samoylov (JINR)

Quark fragmentation measurement Scheme F = ED ⇒ D = E-1F Fπ = (Fee±, Fℓp+,Fℓn+,Fℓp-,Fℓn-, Fνp+,Fνn+,Fνp-,Fνn-,Fνp+,Fνn+,Fνp-,Fνn-) Dπ = (Dd+,Du+,Ds+,Dc+, Mp,d+,Mp,d-,Mp,u+,Mp,u-,Mp,d+,Mp,d-,Mp,u+,Mp,u-,Mp,s-) F, E, D ( z,pT ; { s | x,Q2 } ) NOMAD Durham HepData http://hepdata.cedar.ac.uk/ (more than 100 experimental DATA) See talk by Svetlana Starikova Charm dimuons in NOMAD Oleg Samoylov (JINR)

Current JINR activity at CERN More precise knowledge of the Strange sea of the Nucleon allows to make more accurate prediction of strange particles production in pp collisions (ATLAS, CMS) Measurement of fragmentation functions Dq and Mp,q provides better estimation of spin transfer from quark to produced particles (COMPASS) Improvement of neutrino-induced charm dimuon production can reduce uncertainty of charm background prediction for νμ → ντ oscillation experiments approx. by a factor 2 (OPERA) Charm dimuons in NOMAD Oleg Samoylov (JINR)

Muon neutrino from Atmospheric charm The Baikal experiment is interesting in prediction for cross-sections of charm particle productions in atmospheric nuclear cascade with generation of the muonic neutrino. In collaboration with N.Budnev and S.Sinegovsky from ISU and API (Irkutsk) we plan to calculate neutrino flux prediction for different zenith angles using parameterization of the spectrum of primary cosmic rays in wide energy interval (including ``knee'' region). Charm dimuons in NOMAD Oleg Samoylov (JINR)

Publications in 2011 and Acknowledgements O.Samoylov, R.Petti, PEPAN Lett., 2011, Vol.8, №7 (170) Pp.1252-1261 A.Edemskaya, D.Naumov, O.Samoylov, PEPAN Lett., 2011, Vol.8, №7 (170) Pp.1276-1281 O.Samoylov, Proceedings of the PANIC-11 conf., 2011, MIT (Cambridge, USA) O.Samoylov, Proceedings of the AYSS’11 conf., 2011, JINR (Dubna, Russia) Pp.114 Work has been done in collaboration with R.Petti (USC) and D.Naumov (JINR), with participation of M.Gonchar (JINR), A.Edemskaya (ISU), S.Starikova (ISU). We are grateful to V.Cavasinni, L.Camilleri, L.DiLella for stimulating discussions of this work. This work is partially supported by JINR grant, CERN, RFBR grant, RF Targeted Program “Research and Research-Human Resources for Innovating Russia”. Charm dimuons in NOMAD Oleg Samoylov (JINR)

Oleg Samoylov (JINR, Dubna) @ AYSS’12 conf., Feb. 6-11, 2012 Precise measurement of Charm Dimuon production cross-section in νN interactions and its various applications Oleg Samoylov (JINR, Dubna) @ AYSS’12 conf., Feb. 6-11, 2012