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非最小超对称的一些研究. 中科院理论物理所. 杨 金 民. arXiv: 0801.1169; 0810.0751; 0810.0989; 0901.1437; 0901.1437 . 2009.5.4 于北京大学高能物理研究中心. 目录. 1. 模型介绍 : MSSM,NMSSM,nMSSM 2. 唯象研究. 2.1 目前的实验限制 2.2 可允许的参数空间 2.3 Zbb 反常 2.4 B- 介子的双轻衰变 2.5 超对称粒子的残留效应. 3 、结论. 1. 模型. 精细调节. 大统一. 暗物质. 超对称.
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非最小超对称的一些研究 中科院理论物理所 杨 金 民 arXiv: 0801.1169; 0810.0751; 0810.0989; 0901.1437; 0901.1437 2009.5.4 于北京大学高能物理研究中心
目录 1. 模型介绍: MSSM,NMSSM,nMSSM 2. 唯象研究 2.1 目前的实验限制 2.2 可允许的参数空间 2.3 Zbb 反常 2.4 B-介子的双轻衰变 2.5 超对称粒子的残留效应 3、结论
1. 模型 精细调节 大统一 暗物质 超对称 Electroweak Baryogenesis 宇宙暴涨 Affleck-Dine Baryogenesis
R-conserving SUSY Models MSSM, CMSSM (mSUGRA, GMSB, AMSB) NMSSM,nMSSM Split-SUSY · · · • R-violating SUSY Models
MSSM NMSSM, nMSSM CMSSM -problem little hierarchy
-problem in MSSM: Kim, Nilles, PLB138, 150 dimensionful parameter conserving SUSY should be at Planck scale or 0 chargino is too light =0 only one Higgs-doublet gets vev
little hierarchy in MSSM: • Experimental lower bound need sizable loop effects ! mh 114 GeV (95 GeV) • Theoretical upper bound mh 90GeV (tree-level) ~ 500 GeV 135GeV (loop-level) 100 GeV
NMSSM, nMSSM: • Dynamical solution to -problem • Solve little hierarchy problem Field Content: MSSM + singlet no dimensionful parameter (NMSSM) SUSY-conserving part: naturally small dimensionful parameter (nMSSM) 特点 SUSY breaking ( < TeV ) dimensionful soft parameters (TeV) SUSY-breaking part: trigger EWSB ( < TeV ) generate -term ( < TeV )
motivated from top-down view ? E6 models (superstring-inspired) string scale SO(10) U(1) … at low energy: S, Hu,Hd+ heavy particles U(1) global PQ cubic term (NMSSM) to break U(1) PQ tadpole (nMSSM)
NMSSM 超势: U(1)B: Q(1/3), U(-1/3), D(-1/3), L(0), E(0), Hu(0), Hd(0), S(0) U(1)L: Q(0), U(0), D(0), L(1), E(-1), Hu(0), Hd(0), S(0) U(1)R: Q(1), U(1), D(1), L(1), E(1), Hu(1), Hd(1), S(1), W(3) 0 U(1)PQ: Q(-1), U(0), D(0), L(-1), E(0), Hu(1), Hd(1), S(-2) 标势: U(1)R Z3 (non-R) U(1)R ( A0, A0 ):PGB (get mass from gaugino mass term & QCD 反常)
NMSSM domain wall: Z3 ( X ei2/3X ) 自发破却 domain wall must disappear before BBN 要求 Z3-breaking term in Veff • impose discrete R-symmetry on W • 引入high-order non-renormalizable operator to W multi-loop large enough to break Z3 too small to upset gauge hierarchy
nMSSM 超势: U(1)B: Q(1/3), U(-1/3), D(-1/3), L(0), E(0), Hu(0), Hd(0), S(0) U(1)L: Q(0), U(0), D(0), L(1), E(-1), Hu(0), Hd(0), S(0) U(1)R: Q(1), U(1), D(1), L(1), E(1), Hu(0), Hd(0), S(2), W(2) 0 U(1)PQ: Q(-1), U(0), D(0), L(-1), E(0), Hu(1), Hd(1), S(-2) U(1)R Z2 matter parity
Spectrum of NMSSM/nMSSM: One more CP-odd Higgs (A1or a) MSSM + One more CP-even Higgs One more neutralino
How tosolve -problem? V • Before SUSY breaking SUSY vacuum: Vmin = 0 〈 〉 = 0 EW not broken; no term • With SUSY breaking (TeV) dimensionful soft parameters (TeV) V non-SUSY vacuum: Vmin < 0 〈 〉 0 SUSY breaking ( < TeV ) trigger EWSB ( < TeV ) generate -term ( < TeV )
How to solve little hierarchy? • mh theoretical upper bound MSSM: NMSSM: • mh experimental lower bound suppressed ! has singlet component suppressed !
2.唯象研究 2.1 实验限制 (1) direct bounds: • LEP I • LEP II • Tevatron • LEP II
V (2) Stability of Higgs Potential true (physical) vaccum local vaccum (3) Cosmic Dark Matter (WMAP)
(4) Precision Electroweak Data 1 ,2 ,3 (S, T, U) • Rb • = (Zbb)/ (Zhadrons) SUSY
(6) 反常磁矩 a
Under all above constraints • scan over parameter space • to find out the allowed part • display the allowed part • predict FCNC B-decay • can solve Zbb anomaly ? • residual SUSY effects
2.2 可存活的参数空间 NMSSM
2.4 FCNC B -Decays SUSY SUSY
=mW =mA1 (integrate out A1) =mb • A1 is heavy • A1 is intermediately heavy • A1 is very light
expt data no expt data
NMSSM Sky-blue points excluded by
NMSSM Sky-blue points excluded by
3. 结论 • is well motivated: • can account for all current expt data: Precision Electroweak Data; Rb Cosmic Dark Matter NMSSM/nMSSM g-2 FCNC B-decays . . . . . . . . . except: Zbb anomaly LHC Super B-factory 暗物质实验 检验模型