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LHC Signatures of SUSY

LHC Signatures of SUSY. Yeong Gyun Kim (KAIST & Sejong U.). LHC and ATLAS/CMS SUSY at the LHC LHC signature of Mirage Mediation tau polarization in SUSY casecade decays. Large Hadron Collider and ATLAS/CMS detectors. LHC (the L arge H adron C ollider) : 2007 ~.

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LHC Signatures of SUSY

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  1. LHC Signatures of SUSY Yeong Gyun Kim (KAIST & Sejong U.) • LHC and ATLAS/CMS • SUSY at the LHC • LHC signature of Mirage Mediation • tau polarization in SUSY casecade decays

  2. Large Hadron Collider and ATLAS/CMS detectors

  3. LHC (the Large Hadron Collider) : 2007 ~ a proton + proton collider at 14 TeV c.m energy in the 26.6 km tunnel 1033 cm-2 s-1 ~ 10 fb-1/yr (low luminosity) 1034 cm-2 s-1 ~ 100 fb-1/yr (high luminosity)

  4. Major LHC parameters Main ring circumference 26.6 km Proton energy 7.0 TeV (7×1012eV) Luminosity 1034 cm-2s-1 Bunch interval, collision frequency f 25 nsec, 40 MHz Number of protons/bunchNB 1011 Beam emittance 3.75×10-6 m mrad Number of main dipoles 1232 Main dipole: length, magnetic field 14.2 m，8.36 Tesla Beam transverse spread at IR sx~ sY 17 mm No. pp collisions / bunch crossing 19 Luminosity sx=sy=16.7mm, sz=7.55mm 285 mrad ~8m (25 ns) Taken from KEKPH07 meeting (T.Kondo)

  5. Assembly, test and installation of magnets Storage of magnets outside Dipole interconnect work Transportation and installation in the tunnel, 25 magnets/week Taken from KEKPH07 meeting (T.Kondo)

  6. LHC near future schedule Taken from KEKPH07 meeting (T.Kondo)

  7. Modern multi-purpose detector at colliders T.Han

  8. Particle signatures left in the detector components T.Han

  9. Scattering cross sections for various SM processes

  10. 40 MHz (40 TB/sec) level 1 - special hardware 75 KHz (75 GB/sec) level 2 - embedded processors 5 KHz (5 GB/sec) level 3 - PCs 100 Hz (100 MB/sec) data recording & offline analysis Taken from D. Foster’s talk Balloon (30 Km) CD stack with 1 year LHC data! (~ 20 Km) Concorde (15 Km) ~15 PetaBytes of data each year Analysis will need the computing power of ~ 100,000 of today's fastest PC processors! Mt. Blanc (4.8 Km) David Foster CERN IT-CS

  11. SUSY at the LHC

  12. Minimal Supersymmetric Standard Model (MSSM) • SM fields plus an extra Higgs doublet • and their superpartners • SU(3) x SU(2) x U(1) gauge symmetry and • Renormalizability • R-parity conservation (to avoid fast proton decay) ( B: baryon number, L: lepton number S: spin ) = +1 for ordinary particles = -1 for their superpartners Sparticle are produced in pairs The Lightest SUSY Particle (LSP) is STABLE • Soft Supersymmetry Breaking

  13. Polesello at Paris (Nov. 06)

  14. Polesello at Paris (Nov. 06)

  15. Polesello at Paris (Nov. 06)

  16. Polesello at Paris (Nov. 06)

  17. Polesello at Paris (Nov. 06)

  18. Polesello at Paris (Nov. 06)

  19. Polesello at Paris (Nov. 06)

  20. LHC signature of Mirage Mediation In collaboration with W.Cho, K.Y.Lee, C.Park, Y.Shimizu (KAIST) Ref) hep-ph/0703163

  21. Mirage Mediation In KKLT-type moduli stabilization scenario • Modulus mediated contribution to SSB parameters at MGUT can be comparable to the anomaly mediated one O (m3/2 /4p2) when the gravitino mass m3/2 ~ 10 TeV. • Depending upon the anomaly to modulus mediation ratio the model can lead to a highly distinctive pattern of superpaticle masses at low energy scale.

  22. The soft parameters at MGUT are determined to be where aijk = ai + aj + ak, and ci parameterize the pattern of the pure modulus mediated soft masses. ba and gi : beta function and anomalous dim.

  23. An interesting consequence of this mixed modulus-anomaly mediation is that soft masses are unified at a mirage messenger scale For instance,

  24. modulus Kahler potential modulus superpotential matter Kahler metric gauge kinetic function uplifting potential • A Benchmark Model The original KKLT compactification of IIB theory gives (T : Calabi-Yau volume modulus) ni are rational numbers depending on the origin of matter superfield.

  25. A benchmark point for collider study alpha = 1 M0 = 500 GeV aM=cM=1/2 aH=cH=0 tan(beta)=10

  26. Mirage benchmark point alpha=1, M0=500 GeV, aM=cM=1/2, aH=cH=0, tanb=10 (M1=367 GeV, M2=461 GeV, mu=475 GeV at EW scale) m_gluino= 884 GeV, m_dL=776 GeV, m_t1=545 GeV m_N1 = 355 GeV, m_N2 = 416 GeV, m_eR = 382 GeV (cf. mSUGRA ) • Cross section for SUSY events ~ 6 pb • The cascade decay is open ! (m_N2 > m_eR) We generated SUSY events ( ~ 30 fb-1 luminosity) using PYTHIA (event generator) + PGS (detector simulation)

  27. Precision measurements of sparticle masses at the LHC is open, When the cascade decay a clean SUSY signal is l l + jets + missing events.

  28. Event Selection Cuts.

  29. Di-lepton invariant mass distribution for the mirage point1 with 30 fb-1 lumi. Mll (max) ~ 60 GeV well matched with the generated value

  30. Various distributions for the mirage point m_squark, m_slepton, m_N2, and m_N1 can be determined.

  31. Gluino and squark mass measurement Di-jet invariant mass

  32. Gluino and squark mass measurement Di-jet invariant mass

  33. Gluino and squark mass measurement Stransverse mass m_qR vs m_N1

  34. Stransverse mass Lester and Summers (1999) For where

  35. ‘Model-Independent’ Masses

  36. The mass ratio of gluino to LSP which is quite distinctive from the prediction of GUT unification of gaugino masses.

  37. Determination of model parameters • Gluino, squark and slepton masses • M0, alpha and cM • Neutralino masses  Mu (EW scale), tan(beta)  cH and tan(beta)

  38. Determination of model parameters

  39. Conclusions • We have investigated LHC signature of mirage mediation • by performing a Monte Carlo study for a benchmark point. • SUSY particle masses are determined in a model independent way. In particular, the measured ratio well reproduce theoretical input value of the benchmark point. Therefore, the benchmark scenario may be distinguishable experimentally from other SUSY scenario in which gaugino masses are unified at GUT scale. • Model parameters were obtained from a global fit to observable and well agree with the input values.

  40. Tau Polarization in SUSY Cascade decays In collaboration with S.Y.Choi, K.Hagiwara, K.Mawatari, P.M Zerwas Ref) hep-ph/0612237

  41. Much attention has been paid in the recent past to the SPS1a cascade (R-type sleptons) • So far, cascades have primarily been studied involving first and second generation leptons/sleptons. • In this work, we explore how the polarization of tau leptons • can be exploited to study R / L chirality and mixing effects • in stau and neutralino sector

  42. Single pion decays of tau as polarization analyzer • Fragmentation functions for pions (z : the fraction of the energy transferred from the polarized tau’s to the pion’s R / L : tau chirality )  Pion from right-handed polarized tau- is harder than the one from left-handed polarized tau-

  43. Netralino decay ( N2  stau_R tau_R  N1 tau_R tau _R) (results in hard pions) (for N1, N2 gauginos) Similarly, stau_L gives L L tau pair, which results in soft pions.

  44. Invariant mass distribution of tau-tau and pi-pi parings

  45. m (pi-pi) distribution for SUSY (SPS1a) and UED’ SPS1a : RL type UED’ : LL type

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