Higgs discovery and BSM Mihoko M. Nojiri 12 年 11 月 12 日月曜日
Higgs discovery at the LHC • Higgs boson: The Last missing particle of the SM particles • Probably starting point of “the Beyond the stard model” • why we think so, and how it conflicts with data 12 年 11 月 12 日月曜日
Standard model of particle physics history • Discover the symmetry “SU(3)xSU(2)xU(1)” out from interactions involving mesons, leptons, and baryons • finding “the three generation in the matter sector” • The SM identify “universal forces” to the gauge symmetry, representation (charge) difference leads interaction difference. ? • putting origin of the symmetry breaking (“mass”) H to nature of the spin 0 sector ( Higgs boson ). 12 年 11 月 12 日月曜日
discovery summary • Higgs couples to massive objects in the tree level, tt, bb, ZZ, WW... • discovery in photon and lepton channel H →γγ H → ZZ and H → WW. We can only measure (procution) x (branching ratio) at LHC. • production gg → H dominant, subdominant WW, ZZ → H contribution is seen. The two process overlap significantly. 12 年 11 月 12 日月曜日
question on the mass value Are we in meta stable vacuum or there are new physics in between? is this consistent with cosmology? In4’ 182 IC T~06 T~ 0.4 180 EW vacuum: 8 unstable 6 1.0.35 178 4 T~0.3 176 [ GeV ] 95%CL T.0.2 174 meta- stable m pole 172 t 170 168 ILC stable LHC 166 Tev ⊕ lHC V( φ )=-m2 φ 2+ λφ 4 164 120 122 124 126 128 130 132 Fig. 18. The temperature dependent potential for m~,55, M H [ GeV ] = 50 GeV and for m, = 240 0eV. Here, V 8V/m~1~~, and units of o’ = 1 are used. but λ get negative correction at large φ We are on the meta stable vacuum? or there is something between 100GeV to 10 19 GeV 12 年 11 月 12 日月曜日
question on the mass value Are we in meta stable vacuum or there are new physics in between? is this consistent with cosmology? In4’ 182 IC T~06 T~ 0.4 180 EW vacuum: 8 unstable 6 1.0.35 178 4 T~0.3 176 [ GeV ] 95%CL T.0.2 174 meta- stable m pole 172 t 170 168 ILC stable LHC 166 Tev ⊕ lHC V( φ )=-m2 φ 2+ λφ 4 164 120 122 124 126 128 130 132 Fig. 18. The temperature dependent potential for m~,55, M H [ GeV ] = 50 GeV and for m, = 240 0eV. Here, V 8V/m~1~~, and units of o’ = 1 are used. but λ get negative correction at large φ We are on the meta stable vacuum? or there is something between 100GeV to 10 19 GeV 12 年 11 月 12 日月曜日
New Physics, Clue Fine tuning in the Higgs sector γ top W,Z, higgs if scale of momentum cut off Λ =5TeV ∼ − (2 TeV) 2 − 3 8 π 2 λ 2 t Λ 2 top loop ∼ (700 GeV) 2 64 π 2 g 2 Λ 2 9 SU (2) gauge boson loops ∼ (500 GeV) 2 . 1 16 π 2 λ 2 Λ 2 Higgs loop Others are reasonable Why Higgs vev is O(200) GeV?? gauge two point m f log Λ fermion mass function Π µ ν = ( g µ ν p 2 − p µ p ν ) Π 12 年 11 月 12 日月曜日
Classic Solution:Supersymmetry • exchange boson and fermion. φ ↔ ψ • sfermions(0), gaugino(1/2), higgsinos(1/2) • boson and fermion are in the same multiplet; chiral symmetry extended to bosons. No quadratic divergence • No new dimensionless coupling and no quadratic divergence • Higgs 4 point coupling is written by gauge coupling. (no negative 4 point coupling. ) • gauge coupling unification • R parity in MSSM . New stable particle → DM candidate. 12 年 11 月 12 日月曜日
Higgs 4 point coupling at low energy tree level Higgs mass < mZ + additional correction to from stop sector Low�energy� effective�theory� λ without�SUSY� threshold� correction� SM RGE running give extra Yt 4 logm stop /m t ∝ Xt 4 (stop left right mixing ) gauge coupling (SUSY relation) mt mstop scale 12 年 11 月 12 日月曜日
Higgs mass vs SUSY large stop large stop mixing required for mixing light stop mass in model independent approach t r a p l a n o g a i d f f o large SUSY scale required in simple gauge and anomaly mediation The difference comes from model constraint to A parameters => Huge Tension M S = p m ˜ t 1 m ˜ t 2 parameter X in the stop sect 12 年 11 月 12 日月曜日
Higgs mass vs SUSY large stop large stop mixing required for mixing light stop mass in model independent approach t r a p l a n o g a i d f f o large SUSY scale required in simple gauge and anomaly mediation The difference comes from model constraint to A parameters => Huge Tension M S = p m ˜ t 1 m ˜ t 2 parameter X in the stop sect 12 年 11 月 12 日月曜日
limit at 8TeV (from recent ATLAS) SUSY > (or maybe >>) 1TeV, Does this cause fine turning? under the assumption of universal SUSY breaking (MSUGRA) , sleptons are much above 300 GeV 12 年 11 月 12 日月曜日
Basic collider objects and supersymmetry DM Missing PT New particle New particle DM 12 年 11 月 12 日月曜日
really SUSY particles are so heavy? • Too large fine turning? Correction to the higgs mass 142 exceed higgs mass 140 138 136 134 132 • Is this such a big problem? GUT/weak scale fine 130 m h 128 turning has been solved. We have fine turning in [GeV] 126 124 vacuum energy anyway.. 122 120 118 116 114 1 2 3 4 5 6 7 8 9 10 • By extending model to Next Minimal SUSY , higgs tan β masses upper limit increase → allowing light SUSY Figure 1: Upper bound on the lightest Higgs mass in the NMSSM for m top = 178 GeV (thick full line: m A arbitrary, thick dotted line: m A = 1 TeV) and m top = 171 . 4 GeV (thin full line: m A arbitrary, thick dotted line: m A = 1 TeV) and in the MSSM (with particles. m A = 1 TeV) for m top = 178 GeV (thick dashed line) and m top = 171 . 4 GeV (thin dashed line) as obtained with NMHDECAY as a function of tan β . Squark and gluino masses are 1 TeV and A top = 2 . 5 TeV. d to 45 • contribution from 4th generation can also 40 vacuum instability contribute s 35 stau NLSP neutralino 30 LEP 25 20 s • Higgs mass raised by U’, Q’ loop 15 10 m S(F) : vector scalar(fermion) mass で 5 実際，持ち上がりました。 600 800 1000 1200 1400 1600 1800 2000 2200 12 年 11 月 12 日月曜日
stop search Direct search limit are actually not so strong allows for relatively light stop for NMSSM too close to top mass toward low pT with a lepton 2 lepton is too small more gain for 0 lepton channel 12 年 11 月 12 日月曜日
if light stop is found Entries 2174 Entries 2174 Mean Mean -0.06643 -0.06643 0.08 • stop mixing makes the lighter stop RMS 0.4714 RMS 0.4714 0.07 light 0.06 0.05 0.04 • model is NMSSM so that stop is 0.03 need not to be light. 0.02 0.01 right hand scalar top • stop mixing → top polarization 0 -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 from stop decay(visible at LHC) cos theta_bt costheta_reco_h costheta_reco_h Entries 2247 Entries 2247 Mean 0.1028 Mean 0.1028 0.07 RMS 0.485 RMS 0.485 0.06 b jet 0.05 top 0.04 0.03 0.02 left hand scalar top 0.01 0 -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 Biplob Bhattacherjee Sourav K Mandal Mihoko.M Nojiri in preparation 12 年 11 月 12 日月曜日
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