Transcript Slide 1
SUSY studies at the TESLA collider H. Nieto-Chaupis & G. Klämke (In collaboration with K. Mönig, H. Nowak, and A. Stahl. ) DESY-Zeuthen LCWS - Durham, UK Sep 01 - 04 2004 At this talk : The TESLA photon collider (very brief descriptio n). The SPS1a scenario and some available BRs. Sleptons : analysis and precision studies. ~ studies at alternativ e scenario. 1 Summary and future directions . TheTESLA photon collider Simulation achieved by V. Telnov Laser e c 56 mrad - ee- e- 2 ,1 mm Simulation achieved by G. Klemz (Up to 5 are considered ) The photon collider will be an interestin g window 8 to explore Higgs and SUSY (complemen tary to LC). Slepton sector : high cross sections (t channel only) 6 Polarization is assumed (Pe - 80%) and J 0. dL/dW [10 32 -1 -2 -1 eV cm s ] 10 4 Simulation with Pile - Up events : mandatory. 2 Emax 0 0 100 200 300 photon energy [GeV] 400 500 x Ee x 1 x 4Ee me- Ee 250 GeV; 1.17 eV; x 4.5 Emax 0.82 Ee The SPS1a scenario and some available BRs. Gravity - mediated SUSY - breaking : mSUGRA only 5 free parameters . The SPS1a scenario : m1/2 250 GeV, m0 100 GeV, A0 100 GeV, tan 10 GeV, and sign( ) 1 ~ ~ lR lL ~ ~ lR lR 100% ~ lR ~10l ~10l ~ ~ lL lL ~50% ~ lL ~10l ~10l Right slepton : huge background(ee- E or E ) Left Slepton : cascadedecays from ~20 . ~ ~ L L ~ 0 1 (e.g.): ~0 1 ~0 2 ~ 1 54.9633 ~0 ~0 1 1 16.8814 28.1553 ~0 ~0 1 2 ~0 ~ 1 1 15.4750 54.9633 ~0 30.2096 ~0 ~0 16~.8814 ~ ~0 1 1 ~ ~0 1 2 ~ ~ 1 1 28.1553 15.4750 4.7530 7.9272 2 1 2 1 9.2785 9.2785 ~ ~ 0 2 0 2 2.8498 ~0 ~ 2 1 4.7530 L ( se -e- 600 GeV /500 GeV) L 1000 fb /year 29.09 fb / 88.16 fb ~ R 29.09 fb/88.16 fb 36.27 fb ~ ~1 ~ L ~ ~1 0.34 fb ~2 ~2 ~ 1 170.82 fb ~ 1 ~0 1 ~2 ~1 ~ 1 4.31 fb ~1 ~0 1 1 ~ 0 1 ~ 0 1 ~ ~ L L ~ ~ ~ ~ 1 1 1 W W (2) W W (3) W W (2) W W (3) 1 ~1~1 ~ ~ 2 ~ ~ 1 e ~2~2 ~ ~ e 1 ~ e ~0 1 ~2 33.50 fb ~0 1 W W (3) ~2~2 W W (2) ~ ~ W W (3) 1 1 ~0 ~1 1 W W (2) ~1~1 W W (1) ~0 1 ~ 0.83 fb 1 1 L 26.82 fb ~2~2 ~ ~ 1 L ~ R 10.96 fb ~ L 1 ~0 1 ~ ~1~1 W W (1) ~0 ~ R R Background Main mode -1 2 W W (2) W W (3) R R Sleptons : analysis and precision studies. Sleptons : ~R analysis SHERPA SIMDET Analysis achieved at se -e - 500 GeV Masses : kinematica lly accesible. L 113 fb -1 88 fb Signal Cuts : 15 GeV E 105 Accop 3.05 Rad Accoli 3.00 Rad Background Visible energy 150 GeV Full p 100 GeV. Invariant Mass 150 GeV Eff 87.45% Pur 75.97% Stat. Error 1.15% ~R identifica tion good accuracy ! Sleptons : ~L analysis se e - 600 GeV, L 250 fb -1 collider e e LC SHERPA PYTHIA SIMDET + PILE-UP Left smuon present rich physics to difference to e e - collider (flat spectrum). Due to ~20 and ~1 couplings, pronunced peaks could be observed at the lepton spectrum. Peaks could tells us something about kinematics . Pions and photons are low energetics : analysis ee n become difficult with pile - up events. Photons FS plays important role at low energy. ~L ~10 Muon are highly energetics with high missing energy. Main background : W W - and ~ ~ : smeared missing mass. R R Eff 0.400, Pur 0.398, Br 0.5498 0.01398 (B NSel .Pur/L. .Eff). Assumption : L 5% and 1%. Statistica l error 2.038% - - final state analysis. Muon tagging : at least 1 must be inside ~L ~10 region. E tipycally 50 GeV. At least 1 comming from cascade decay with very low energy ( 30 GeV) Main background : Jets (but fortunatel y it have low invariant mass) Cut imposed on invariant mass sharp peak at E4 8 GeV. BR 0.04798 0.0023(4.86% St.) Sleptons : ~1 analysis SHERPA (4 particles FS) Scalar tau presents an important background , mainly from and charginos. 428 GeV Missing Energy 592 GeV Missing Mass 498 GeV predominan ce of Invariant Mass between 4 GeV and 40 GeV. Pur 11.2 %, Eff 77.6% and Stat. Error 7.22% Chargino studies (G. Klämke) Goal : Direct measuremen t of Chargino branching ratio. Process : ~ ~ W ~ 0W ~ 0 1 1 1 1 mSUGRA parameters : m0 130 GeV, m1/2 250 GeV, A0 -100 GeV, tan 9, and sign 1 Masses and BRs : m( ~1 ) 180 GeV, m( ~10 ) 95 GeV, m(~1 ) 159 GeV, BR(~ W ~ 0 ) 26.2%, BR(~ ~ ) 72.5% 1 1 1 1 Analysis done for e - beam energy 250 GeV and 300 GeV. Signal Cross Sections ( calculated with SHERPA) (250 GeV) 2.62 fb (300 GeV) 7.98 fb Signal events per 1000 fb-1 (1 year) N(250 GeV) 2620 N(300 GeV) 7980 Background ( 4 jets) Cross Sections (250 GeV) 13.7 pb (300 GeV) 13.4 pb Signal events per 1000 fb-1 N(250 GeV) 13.7 10 6 N(300 GeV) 13.4 10 6 Pile - Up events Low energy hadrons, induced by Beamstrahl ung & Compton photons. 1.8 events per BX (average). Reduced by cuts on polar angle and vertex of hadron tracks. Some cut - variables Acoplanarity Background (250 GeV) Signal (250 GeV) PT Missing W - Energy After cuts (250/300 GeV) : Nsignal 529/1919 , Nbackg 6951/46206, Eff 20.2/24.1% , Pur 7.07/3.99 % N (1000 fb -1 ) 16.3/11.4% N BR(~1 W ~10 ) 8.2% (250 GeV) 5.7% (300 GeV) Fittino: general fit of MSSM parameters by using the LC observables (e.g. cross-sections & masses). Some MSSM parameters are fitted with FITTINO (others fixed): Parameter Input Value Fit-Error without BR Fit-Error with BR (5.7%) tan 9.0 6.29% 4.69% M1 99.54 0.092% 0.073% M2 192.57 0.140% 0.083% the measurement of BR(~1 W ~10 ) can improve the error of the fitted MSSMparameters! Summary and future directions At this analysis we have assessed the capability of the TESLA photon collider at the low energy SUSY sector. The pile - up events put down efficienci es ( increase the error at low energy region 1 GeV). Definiteve ly the slepton sector present interestin g characteri stics. Left sleptons contain rich physics but it have also irreductib le Bg. Stau studies : tau finder could enhance the purity (in progress). Chargino studies : to study stau channel. We are interested at particles with observables available at the photon collider (500 - 800 energies) at SPS1a scenario(m SUGRA if SUSY low energy exist! ) ~R (143.05 GeV) 0.2185 GeV ~1 (134.44 GeV) ~L (204.69 GeV) 0.2382 GeV ~2 (207.68 GeV) ~1 (181.65 GeV) 0.0138 GeV ~2 (375.27 GeV) ~ 0 ( 95.48 GeV) 0. GeV ~ 0 (181.65 GeV) 1 2 0.1571 GeV 0.2820 GeV 2.5540 GeV 0.0187 GeV The Cross Sections are calculated from SHERPA program and SUSY spectrum is obtained from the ISAJET(7.69) and SUSY decays are calculated from PYTHIA(6.3) Outline ●The smuon left decay into SPS1a scenario. ●A brief approach to the TESLA photon collider. ●Iterative measurements. ●Synopsis. ● The smuon left decays into SPS1a scenario. ISAJET 7.69 is used to generate the spectrum of masses, widths and BRs. ~0 Prefered mode: ~10 ~10 (~30.20%) . Other modes containing have 2 high multiplicity final state (cascade decays from tau lepton). Charguino does decay substantially into staus. ~ 0 LSP candidate, m=95.5 Assumption: universal BR right sleptons = 1 ( 1 ~L ~L ~10 ~1 ~20 ~10 54.9633 ~ 0 ~ 0 16.8814 ~ 0 ~ 0 28.1553 ~ 0 ~ 54.9633 ~ 0 30.2096 ~ 0 ~ 0 9.2785 ~ 0 ~ 0 15.4750 ~ 0 ~ 16.8814 ~ 9.2785 ~ ~ 0 2.8498 ~ ~ 0 4.7530 ~ ~ 28.1553 15.4750 4.7530 2 1 1 1 2 1 1 1 1 2 2 1 2 2 1 1 2 1 1 1 7.9272 ) GeV ~L ~10 ~1 ~1 Slepton prefers a Wino /e l ~10 ~ lR l → cascade 10 Charguino can decay into W and staus. ~20 1 20 Slepton only decays to a Bino ~L Slepton decays come from the coupling 20 have more complicate decays. Cascade decays could be observed if we have high efficiency. Up to 4 muons FS could be observed SUSY also give us important background Available final states Final State ~ 0 1 ~10e e ~10 ~10 ~10 ~10 ~10 ~10e ~10e e ~10e ~ 0e 1 ~10 ~ 0 e 1 ~10 ~ 0 1 Br Final State Br 0.549633 0.011073 0.011084 0.004393 ~10 v ~10 ve 0.006308 0.004512 0.002861 0.006308 ~10 v ~10 v ~10 ~10e ~ 0 0.009058 0.044289 ~ 0 0.063590 ~10 0.002849 0.002809 1 0.004512 0.004649 0.002938 0.006479 0.002861 0.002938 0.001862 0.004107 0.006479 0.004107 1 ~10e ~ 0 1 0.045487 0.028837 0.000495 ~10e 0.000509 ~10 ~ 0 0.000322 1 0.000711 ●A Laser Beam brief approach to the TESLA photon collider Conceptual Scheme of a Gamma-Gamma Collider. Electron Beam CP IP Lγγ Electron Beam J=0, ECM =500 GeV CP Laser Beam Additional effects also take place here!! Emax x Ee x 1 x 4Ee Non-linear effects 2 2 2 2 2 n r e F e 2 2 2 2 m c 0 me- √sγγ Ee 250 GeV; 1.17 eV; x 4.5 Emax 0.82 Ee e e