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Published byZaire Spurling Modified over 2 years ago

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SUPERSYMMETRY Most popular solution to the hierarchy problem. Symmetry between fermions, and bosons With same mass and quantum number 3

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SUPERFIELD contains Fermion/Boson and its SUSY partner Boson/ Fermion SM fermion bosonic, spin 0, superpartner, sfermions. SM boson spin ½ fermion gauge boson, gaugino. Higgs, higgsino 4

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Each SM field is promoted to a superfield. 5

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1) We do not see scalar electrons or fermionic gluons! Supersymmetry should be broken. 1) Still solution to hierarchy problem as long as SUSY-breaking operators are “soft” (d<4). 6

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1)Mass and mixing term for sleptons, squarks and higgses. 2) Majorana mass for the gauginos 3) Trilinear couplings 7

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MSSM Higgs sector two higgs doublets model Yukawa interactions contained in the superpotential, holomorphic function of the superfields 8

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H d same gauge numbers of a lepton field, but the sneutrino can’t be a Higgs field. Is it possible H d L ? 9

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1) H d is necessary to cancel the H u anomalies. 2) Sneutrino VeV violates lepton number, constraints on the neutrino mass impose the VeV to be very small. 10

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to give mass to the Higgsino But Lepton and baryon number are not accidental symmetries ex. fast proton decay 11

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Proton decay Majorana neutrino mass fig. hep-ph/ v2 12

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Typical solution: impose a discrete symmetry called R parity Fermionic and bosonic component of a superfield have different R parity! SM particle even under R parity SUSY partners odd under it Distinctive pheno at the LHC! 13

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We introduce these terms in the superpotential Couplings are highly constrained from the experimental bounds ( neutrino mass) Interesting and different pheno at the LHC. 14

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R parity contained in U(1) R continuous symmetry. U(1) R acts differently on the fermionic and bosonic component of a field: 15

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Gauginos Majorana mass are forbidden by R symmetry MSSM is not R symmetry invariant Gauginos should be Dirac fermions! 16

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New Adjoints superfields for each SM gauge group to give Dirac mass to the gauginos Supersoft SUSY breaking operator, Fox, Nelson, Weiner, 2002 D term spurion 17

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Enlarged Higgs sector, two new doublets R u R d New Adjoints superfields for each SM gauge group to give Dirac mass to the gauginos arXiv:: [hep-ph] 18

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Forbidden by R symmetry Necessary to give mass to the higgsino W superpotential R charge 2 19

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1)Dirac gauginos 2)No left/right mixing as trilinear soft couplings are forbidden by R symmetry 3)Enlarged Higgs sector, inert doublets 4) Large flavor violation compatible with bounds 20

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HdHd LaLa a=e or μ or τ 21

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One of the sneutrino plays the role of the down type Higgs H d Necessary to cancel anomalies and to give mass to the Higgsino 22

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SM particle don’t carry R charge beside electron and its neutrino. SUSY partners carry all R charge besides the slectron, and the electronic sneutrino Ex:Q i R charge 1, fermion R charge 1-1=0 23

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OUR MODEL: The electronic sneutrino does not carry R charge/lepton number A sneutrino VeV does not induce a neutrino mass! 24

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Just two Higgs doublets as in the MSSM, one is inert as the lepton field gives mass to the down type fermions Need just to add the adjoints superfields to the MSSM spectrum 25

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is nulll. Yukawa coupling for the electron is generated by SUSY breaking Higgsino mass 26

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v a sneutrino VeV a=e or μ or τ 30

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Constraints from the gauge bosons couplings Lepton universality violation 31

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GeV 32

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Heavy gauginos, large sneutrino VeV a=e a=μ,τ 33

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Down type Yukawa couplings = R p violating couplings, EWPM bounds, no neutrino bounds! 34

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Trilinear R p violating couplings induce neutrino mass, in our case they don’t. Majorana neutrino mass forbidden by R symmetry fig. hep-ph/ v2 35

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Contribution to G F Semileptonic Meson decay fig. hep-ph/ v2 36

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Tau Yukawa Bottom quark Yukawa Very high tanβ region excluded 37

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Our case Neutrino bounds can have a sizeable branching ratio! 38

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Majorana mass for gauginos Trilinear scalar coupling 39

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Neutrino mass generated by Left/Right mixing generated by anomaly mediation fig. hep-ph/ v2 40

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Bounds on SUSY breaking Scale, F <10 16 (GeV) 2 Gauge mediation 41

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Unstable Possible Dark matter candidate BUT… 43

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The relic density should be very small Very low reheating temperature required! 44

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GeV 45

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Mu Bmu problem Yukawa coupling for the Higgs/Lepton Electroweak symmetry breaking LHC Phenomenology 48

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X spurion field Higgsino mass Mixing term 49

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One loop Gauge mediation Fine tuning! 50

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One loop Two loops Gauge mediation No fine tuning 51

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One loop Two loops Different operators. term 52

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One loop Fine tuning! 53

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Solution inspired by model by Giudice,Dvali, Pomarol (1998) Messenger field 54

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More link fields to add For very low scale SUSY breaking Null, Yukawa coupling generated through SUSY breaking 55

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MSSM scalar potential with No mu term for the sneutrino. R d does not develop a VeV, it is an inert doublet R d necessary to cancel the H u anomalies and to give mass to the higgsino. 56

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Our R symmetry impose that ALL the decay chains should end with electrons or electronic neutrinos. Lightest R a particles charged lepton and neutrinos. Multileptons signature at the LHC. Pheno similar to R p violating models. 57

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LEPTO SQUARK Shorter decay chain! But shorter decay and Dirac gauginos as smoking gun. Stronger R p violation in our model Usual scenario R p effects felt just in the decay. 58

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MMRSSM minimal particle content The sneutrino is the down type higgs! Interesting LHC phenomenology Interesting possible scenario for neutrino model building MMRSSM Dark matter candidate ? Axino/Axions sector? 59

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