Search for Heavy Quark Resonances in Two-Photon collisions in the L3 detector Mikhail Levtchenko (INFN Milano) Search for c meson (status) Search for b meson (status) Outlook M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

Two-Photon physics Resonance formation Outgoing e-e+ are undetected (“No TAG”)  Quasi-real photons Final state  neutral unflavored meson R ,with C=+1 M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

c(z-pole) Was studied in z-pole data L=140pb-1 Channels: +- +- +-K+K- Ks0 K K+K- 0 +- +-’ +- Physics Letters B 461 (1999) 155-166 M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

c(z-pole) M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

bTheoretical Prediction M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

Previous searches M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

ALEPH M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

c/b High energy data: L=610pb-1 4 times bigger statistic All decay modes are the same PreSelecion is: 2tracks, 4tracks, 6tracks 2tracks 2photons, 4tracks 2photons, 6tracks 2photons Clean signal from c The most significant decay modes: +-,  K+K-+- Ks0 K K+K-0 M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

c/b Selection +- +- and +-K+K- Four tracks and no photons. Using dE/dx measurement  and K are distinguished with 8% to 21% misidentification Ks0 K Geometrical reconstruction of the secondary vertex of Ks0 +-, invariant mass M(+-)=M(Ks0) 30MeV K+K- 0 Two photons reconstructed as 0 and two tracks observed. c/b  +-0 is forbidden by G parity conservation. +-  reconstruction,  +-0 with |M(+-0 )-M()|< 40MeV +-’, ’ +- reconstruction with |M(+-0 )-M(’)|< 50MeV, ’ 0 +- |M(0 )-M()|< 25MeV M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

c/b Selection a) Effective mass of two photons in K+K- 0 sample b) Effective mass of two photons in +- sample c) Effective mass of +- from Ks0 +- secondary vertex c) Effective mass of three pions photons in +- sample M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

e+e-e+e-K+K-0 c Data(fit): M(c )=2.965+/-0.017 GeV 0 reconstructed from 2 P(K+K-)/(P(+-)+P(K+K-))>20% Data(fit): M(c )=2.965+/-0.017 GeV (c )=0.092+/-0.011 GeV MC(fit): (generated with PDG parameters) M(c )=2.961+/-0.002 GeV (c )=0.083 +/-0.002 GeV =3.68+/-0.08 Nev=30+/-15 M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

e+e-e+e-K+K-0  b M=9.168 +/-0.300 GeV M=9.519 +/-0.300 GeV 0 reconstructed from 2 P(K+K-)/(P(+-)+P(K+K-))>50%  M=9.168 +/-0.300 GeV M=9.519 +/-0.300 GeV M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

e+e-e+e-+- c Data(fit): M(c )=2.953+/-0.025 GeV  reconstructed from 2 Two tracks required Data(fit): M(c )=2.953+/-0.025 GeV (c )=0.067+/-0.017 GeV MC(fit): (generated with PDG parameters) M(c )=2.965+/-0.003 GeV (c )=0.077 +/-0.003 GeV =5.42+/-0.15 Nev=35+/-10 M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

e+e-e+e-+-  b  reconstructed from 2 Two tracks required M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

e+e-e+e-+-’0 c Data(fit): M(c )=2.973+/-0.045 GeV ’ reconstructed from 0 Four tracks required Data(fit): M(c )=2.973+/-0.045 GeV (c )=0.071+/-0.037 GeV MC(fit): (generated with PDG parameters) M(c )=2.981+/-0.005 GeV (c )=0.084 +/-0.005 GeV =0.41 Nev=5+/-4 M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

e+e-e+e-+-’0  c M=9.35 +/-0.320GeV 0 reconstructed from 2 0  M=9.35 +/-0.320GeV M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

e+e-e+e-KsK c Data(fit): M(c )=2.956+/-0.022 GeV Geometrical reconstruction of the secondary vertex of Ks0 +- M(+-)=M(Ks0)30MeV /K separation by dE/dx Data(fit): M(c )=2.956+/-0.022 GeV (c )=0.064+/-0.022 GeV MC(fit): (generated with PDG parameters) M(c )=2.975+/-0.003 GeV (c )=0.082 +/-0.003 GeV =2.23+/-0.05 Nev=35+/-12 M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

e+e-e+e-4tracks c 4K-near threshold 4 - dominated by background So we are using only 2K2 data M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

K+K-+- Data(fit): M(c )=2.989+/-0.011 GeV (c )=0.092+/-0.019 GeV MC(fit): (generated with PDG parameters) M(c )=2.957+/-0.002 GeV (c )=0.066 +/-0.002 GeV =2.52+/-0.05 Nev=30+/-10 M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

Low statistics channels a) R+-(+-0) Nev=4+/-3 b) R+-’(+-) Nev=1+/-1 c) R+-’(0) Nev=5+/-4 d) R+- Nev=8+/-5 M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

b M=9.89+/-0.32 GeV Events/330MeV 08/04/2003 M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

b M=9.36 +/- 0.34GeV M=9.89 +/-0.34GeV GeV Events/330MeV 08/04/2003 M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

c - Sum High energy Data(fit): M(c )=2.965+/-0.017 GeV Nev=72+/-25 M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

Summary on c Weighted average =3.68±0.87(stat)±0.8(sys)±2.0(BR) keV (Published:6.9±1.7(stat)±0.8(sys)±2.0(BR) keV) M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

b - Sum Average effective mass: M = 9.51 ± 0.30 GeV * N(candidates)=6, expected BG – 2.5 *Mass resolution due to detector effects ~ 300 MeV π/K misidentification ~ 50 MeV M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

Summary on b The observation is compatible with the background CL=4% Upper limits on (b)xBR: (b)xBR(K+K-0) <2.83 keV (b)xBR(4 tracks) <0.21 keV (b)xBR(4 tracks 0) <0.50 keV (b)xBR(6 tracks) <0.33 keV (b)xBR(6 tracks 0) <5.50 keV (b)xBR(+-’) <3.00 keV At 95% of C.L. M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003

Conclusion and Outlook New c results Resonance parameters are measured with more precision Two-photon width is calculated New b results 6 candidates of b are well measured and checked Upper limit on two-photon width is given Both of analysis's are completed M.Levtchenko Search for heavy quark resonances in Two-Photon collisions in L3 08/04/2003