Selected Topics in Elementary Particle Physics ( Haupt-Seminar )

Transcription

1 Selected Topics in Elementary Particle Physics ( Haupt-Seminar ) Paola Avella, Veronika Chobanova, Luigi Li Gioi, Christian Kiesling, Hans-Günther Moser, Martin Ritter, Pit Vanhoefer Time: Do, 12 ct -14 Introduction: April 10, 1st seminar on April 24 Place: HS 537, Schellingstr. 4 / V Alternative Seminar room MPI für Physik, Föhringer Ring 6, Zi. 23

2 Subjects, Coaches Standard Model MR, CK Detectors PA, HG Accelerators CK, MR Higgs particle PV Tau decays CK Top physics HG CP Violation LL, VC Neutrinos VC Beyond the Standard Model PV SUSY PV Dark matter MR g-2 LL C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS

3 Addresses of Coaches PA VC LL CK HGM MR PV Paola Avella Veronika Chobanova Luigi Li Gioi Christian Kiesling Hans-Günther Moser Martin Ritter Pit Vanhoefer C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS

4 Standard Model of Particle Physics electr. charge +2/3 electr. charge 0 u u d..., or u d... Mass of particles (in GeV): / Leptons 0 1 >0 >0 > particles : Spin 1/2 (fermions) fields : Spin 1 (bosons) last missing particle found: H the Higgs (126 GeV, Spin 0) C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS

5 It s Finally There C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS

6 Transformations between Fermions Changing flavor by Universal Weak Interactions - m e - - n pe n e e m n n m - n e nm e - G = 2 8 sin Electroweak Unification within Standard Model (SM): Weak coupling basically same as for electromagnetism Fermi s constant a ( q M ) 2 W W SM: d u ud d ud u ne e - W - e sin q W e - n e 1 (Cabibboangle) weak because of propagator C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS

7 C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS

8 C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS

9 Why go Beyond the SM? The Standard Model SU 3 x SU 2 x U 1 (SM) describes all data so far yet: cannot be the correct theory, SM only a low energy approximation Evidence for Physics beyond the Standard Model: Unification of forces incomplete: Gravitation is not included Stability of the Higgs mass unexplained need very high energy (LHC) or very high precision (SuperB factories) Neutrinos are massive (Dirac, Majorana?) Baryon Asymmetry in the Universe is much too large (by 10 orders of magnitude) Dark Matter exists (only 4% of the Universe accounted for by SM) C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS

10 BSM: A Necessity C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS

11 The Solar Neutrino Problem Solar v flux too low!! 600 Tons Carbon Tetrachloride Ray Davis Jr. Nobel-Prize 2002 C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS 2014 Homestake Neutrino Observatory (since 1967) 11

12 Super-Kamiokande (Japan, since 1998) Davis Experiments confirmed t pure water phototubes n n e m Neutrinos have mass! uen e d (from the sun) n d um - m (atmospheric neutrinos from CRs) C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS

13 C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS

14 Top Quark Physics Need for 3 generations (CP violation, Kobayashi-Maskawa 1973) Top quark properties production decay mass, width,. Early searches and hints Predictions from EW precision measurements Discovery at Fermilab, 1995 Top physics at LHC Why is top still of interest? C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS

15 New Physics at the Loop Level. Rare Decays of τ leptons: penguins SM: t n t W - e sin q W e - n e t t H t 0 g e Principle: Deviation of observable from the SM prediction signals NP virtual particles in the loop reveal their existence Hot topic: rare decays of tau leptons: t t t mg mmm mh 0 NP could make these decays possible L NP Can reach very large scales!! need precision (statistics) to challenge the SM C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS

16 C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS

17 BSM: Super Symmetry C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS

18 Dark Matter in Galaxies Rotational speed of luminous matter about 200 km/sec, independent of the radial distance Galaktic plane is embedded in a Halo of non-luminous ( dark ) matter Andromeda-Nebula, distance about 2 Mio Ly C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS 2014 DM Searches New form of matter? 18

19 Accelerators Typical accelerator complex ( collider ): e - e + Beam particle guns N = L s Pre-accelerator (linac) Injection system Magnetic guide field Final focus, collision point All important parameter: Luminosity = N N 4 ps s 1 2 C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS L x y

20 HEP Detector Systems C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS

21 System cross section C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS

22 Dates for the Seminar PA VC CK LL HGM MR PV 10. April x x x x x x x 24. April x x x x x x 8. May x x x x x x 15. May x x x x 22. May x x x x x x 5. June x x x x x 12. June x x x x x 26. June x x 3. July x x x 10. July x x x x x x = coach present C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS

23 Backup C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS

24 Surprising Discoveries in Weak Interactions of Quarks P violated maximally in weak interactions T.D. Lee C.N. Yang 1957 Small CP violation in neutral K system J. Cronin V. Fitch 1980 O(1) CP violation and 3 generations of quarks M. Kobayashi T. Maskawa 2008 C. Kiesling et al., Physik Haupt-Seminar, LMU München, SS