Higgs Boson Mass In GaugeMediated Supersymmetry Breaking Abdelhamid
Higgs Boson Mass In Gauge-Mediated Supersymmetry Breaking Abdelhamid Albaid In collaboration with Prof. K. S. Babu Spring 2012 Physics Seminar Wichita State University April 4 2012
q. Background OUTLINE Ø Standard Model Ø Higgs Mechanism ØFlavor Structure of SM ØShortcomings of SM ØSupersymmetry Ø Interesting Features of MSSM ØSupersymmetry Breaking ØShortcomings of MSSM ØGrand Unification Theory
OUTLINE q. Motivation Ø Higgs Mass Limit in MSSM. Ø Updated Experimental Results on the Higgs mass Ø Gauge Mediated Supersymmetry Breaking (GMSB) Ø Objectives q. Higgs mass in GMSB with messenger-matter Mixing Ø GMSB with Messenger-Matter Mixing Ø Higgs Mass Bounds in the Model Ø Froggatt-Nielsen Mechanism Ø Flavor Violation q. Conclusion
Background Standard Model (SM) Ø Four fundamental interactions 1) 2) 3) 4) Electromagnetic interactions ( Photons) Weak interactions ( W+/W-, Z) Strong interactions (gluons) Gravitational interaction (gravitons) Ø Standard Model gauge group Ø The invariance of local gauge symmetry leads to massless photons and gluons Ø Gauge Symmetry should be broken spontaneously by employing Higgs Mechanism Glashow-Weinberg-Salam Model Quantum Chromodynamics (QCD) SM
Background Standard Model (SM) Ø There is no right handed neutrino in SM. Ø As a consequence of EWSB Ø Higgs particle is predicted by SM and finding it might lead to new physics beyond the SM
Background Flavor Structure in SM Hierarchical Structure ? ? Lepton Sector Neutrino mixing angles Quark Sector Quark mixing angles Is it possible to accommodate large neutrino mixing angles and small quark mixing angles simultaneously in unified framework? Yes, in doubly lopsided structure, [Albaid, 2009, 2011] The hierarchical structure of fermion masses and mixings can be understood by employing Froggatt-Nielsen Mechanism
Background Higgs Mechanism ØHiggs potential ØMinimizing the potential ØThe mass of the Higgs boson ØFor theory remains perturbative
Background Shortcomings of the Standard Model Ø doesn’t contain gravity Ø doesn’t explain neutrino masses. Ø doesn’t have candidate for dark matter Ø no unification of gauge couplings possible Ø gauge hierarchy problem Higgs mass receives huge quantum corrections
Background Shortcomings of the Standard Model cutoff scale The required value A promising scenario that solve the hierarchy problem is supersymmetry (SUSY)
Background Supersymmetry Ø Symmetry between fermions and bosons Q | boson > = | fermion > and Q | fermion > = | boson > Ø Point in superspace: Ø Chiral scalar superfield Scalar fermion Auxiliary Ø langrangian is obtained form Superpotential Ø SM particles have SUSY partner Ø The minimal supersymmetric extension to the SM is MSSM
Background Supersymmetry
Background Interesting Features of Supersymmetry Ø SUSY Solves the instability in the Higgs mass SM contribution SUSY contribution + As a consequence of supersymmetry Quadratic divergence will cancel
Background Interesting Features of Supersymmetry Ø Gauge coupling unification Unification of couplings at high scale Ø has dark matter candidate Ø provides a natural mechanism for EWSB Ø sets upper bound on the lightest Higgs mass < 130 Ge. V Grand Unification Theory ( GUT)
Background Supersymmetry Breaking Ø Can SUSY be an exact symmetry? Ø For each fermionic state there is a bosonic state with the same mass Ø Experimentally excluded, SUSY must be broken symmetry! Ø Supersymmetry is spontaneously broken OR Ø The relation, , must be maintained in an broken supersymmetric theory.
Background Supersymmetry Breaking Ø Classification of Soft breaking terms q scalar mass terms: q trilinear scalar interactions: q gaugino mass terms: q bilinear terms: q soft terms in MSSM:
Background Shortcomings of MSSM Ø Many new free parameters: about 105 free parameters Ø New source of flavor violation (FV) Example: Leptonic Flavor Violation Solution: Assume that the slepton masses are degenerate This can be achieved by adopting GMSB Ø The origin of soft breaking terms Gauge mediated supersymmetry breaking (GMSB) Gravity mediated supersymmetry breaking
Background Grand Unification Model (GUT) Ø The more symmetrical theory is, the more elegant and beautiful it is. Ø One simple group with one gauge coupling is more symmetrical than the SM gauge group. Ø In GUT, fermions are grouped in larger representations (GUT- multiplet) Ø GUT models contain few free parameters MSSM GUT
Background Grand Unification Model Ø The simplest gauge group with rank 4 is SU(5) gauge group. Ø The 15 left-handed fermions of SM can be impeded into two large irreducible representations of SU(5). Ø GUT is a symmetry inside each generations of fermions, therefore it predicts relations among fermion masses Ø In SO(10) GUT
Motivation Higgs Mass Bounds in MSSM 1 -and 2 - loop Maximal Mixing Condition:
Motivation Updated experimental results on the Higgs mass
Motivation Updated experimental results on the Higgs mass Ø The preferred region Ø ATLAS and CMS. An excess of events around 124 -126 Ge. V
Motivation Gauge mediated Supersymmetry breaking Ø Breaking supersymmetry at the renormalizable tree level interactions do not lead to acceptable spectrum. Ø New superfields (messengers fields) Couple to SUSY breaking in the hidden sector Couple indirectly to MSSM fields via gauge interactions Have heavy masses by coupling by gauge singlet superfield
Background Gauge mediated Supersymmetry breaking Ø Gaugino masses generated at one loop order Ø Scalar masses generated at two-loop order Ø Tri-linear soft terms are zero at messenger scale
Motivation Features of Ordinary GMSB Ø Highly predictive Ø Flavor violation processes are naturally suppressed Ø Preserving gauge couplings unification ØIs it possible to obtain maximal mixing ( ) in the ordinary GMSB? No, because Messenger- matter mixing with messenger fields belong to can reproduce
Background The Objectives To construct GMSB model with messenger-matter mixing Ø that raises the lightest Higgs mass to about 125 Ge. V Ø that leads to supersymmetric particles of around sub-Te. V. The above objectives should be consistent with Ø flavor violation processes are suppressed in agreement with experiment. Ø the gravitino has a cosmological preferred sub-ke. V mass.
Higgs mass in GMSB with messenger-matter Mixing GMSB with Messenger-Matter Mixing Ø Messenger fields belong to GUT scale Messenger scale
GMSB with Messenger-Matter Mixing Ø Messenger fields belong to Messenger scale GUT scale Compare with
Higgs Mass bounds in the Ø There are three parameters Model
Higgs mass in GMSB with messenger-matter Mixing Higgs Mass bounds in the Model
Higgs Mass bounds in the Model
Higgs mass in GMSB with messenger-matter Mixing Froggatt-Nielsen Mechanism Ø U(1) flavor symmetry is assumed. Ø there is a SM singlet “ flavon” field Ø U(1) is broken at high scale by Ø The hierarchy of fermion masses and mixings can be explained as a power expansion of
Higgs mass in GMSB with messenger-matter Mixing Froggatt-Nielsen Mechanism Agree with neutrino mixing angles Agree with quark mixing angles Ø Additional couplings
Higgs mass in GMSB with messenger-matter Mixing Flavor Violation Ø Mass Insertion Parameters: The messenger-matter couplings reintroduce the flavor violation are generated by the exotic Yukawa couplings.
Flavor Violation
Conclusion q The SM is not a complete theory, we need to go beyond the SM q Although SUSY has several advantages such solving the hierarchy problem and obtaining the unification of gauge couplings. It contains many free parameters and contains new sources of flavor violation processes. q GMSB scenario not only reduces the free parameters of MSSM from 105 to only 5 parameters but also naturally solves the SUSY flavor problem. q Introducing messenger –matter mixing in GMSB models raises the lightest Higgs mass up to 125 Ge. V along with sub-Te. V mass of supersymmetric particles. Such a mixing would make GMSB models compatible with the recently reported hints on. q These results are consistent with the gauge and exotic Yukawa couplings being perturbative and unified at the GUT scale as well as the FCNC being suppressed in agreement with experimental bounds.
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