# Presentation: 182776

## Lg̃M & LoL @ LHC                   JiJi Fan                        Yale University

- w/ A.D.Simone, M.Schmaltz and W.Skiba
- arXiv: 0808.2052 [hep-ph]

## Low-scale gaugino mediation:lots of leptons at the LHC                      JiJi Fan                   Yale University

- w/ A.D.Simone, M.Schmaltz and W.Skiba
- arXiv: 0808.2052 [hep-ph]

## Finally the LHC starts collecting data!
   Supersymmetry or MSSM will be tested.
 MSSM: 105 soft parameters 
   already constrained by FCNC and CP violation and must have some “organizing principle”.
 Mediation Scheme:

   gravity mediation, gauge mediation, anomaly mediation, gaugino mediation....

-    Supersymmetry or MSSM will be tested.
-  MSSM: 105 soft parameters
-    already constrained by FCNC and CP violation and must have some “organizing principle”.
-  Mediation Scheme:
-    gravity mediation, gauge mediation, anomaly mediation, gaugino mediation....

## Sketches of sample spectrum from different models

           mSugra                             mGMSB w/ N5=1
Sfermions not much lighter than gauginos:  

-            mSugra                             mGMSB w/ N5=1
- Sfermions not much lighter than gauginos:

## Motivation

- Some different spectrum?!
- Scalar superpartners much lighter than gauginos?
- Spectrum of low-scale gaugino mediation

## Gaugino Mediation(Kaplan, Kribs and Schmaltz; Chacko, Luty, Nelson and Ponton 99’)

- At
-  m0  generated radiatively from m1/2
-              : threshold effects at the messenger scale;
-              : threshold effects at the gaugino mass scale;
-              : Log running between the two scales.
- In original models,

## Low-scale Gaugino Mediation( Lg̃M  )A.D. Simone, J.F, M. Schmaltz and W. Skiba (arXiv:0808.2052(hep-ph))

- Low messenger scale, small Log running
-     After including color factors and the log’s, scalar masses are still smaller than gaugino masses by a factor of a few (≥ 2).

## Spectrum of Lg̃M 

- Scalar superpartners much lighter than gauginos; Colored spaticles heavier than non-colored ones.
- The lightest superparners, in the mass increasing order, are the gravitino, right-handed sleptons and **left-handed sleptons**.
- Many decay chains pass through the left-handed sleptons and end in additional leptons.
-       Typical signal:
- Also
**     **

## A simple modelbased on “deconstructed g̃M” (Cheng, Kaplan, Schmaltz and Skiba; Csaki, Erlich, Grojean and Kribs 01’)

- Setup
- At Λ~5 TeV,

## Assume SUSY breaking only couples to the fields charged under B gauge group. 
    (can be realized through extra dimension setup or gauge mediation with messengers only charged under GB...).
Phenomenologically, 
       :  SU(5)B gaugino soft mass;
       :  link fields’ soft mass;
MSSM gaugino mass: 
     at tree-level from the mixing of A and B gauge groups
    In the limit mB « M               
    (M: heavy gauge boson masses)      

-     (can be realized through extra dimension setup or gauge mediation with messengers only charged under GB...).
- Phenomenologically,
-        :  SU(5)B gaugino soft mass;
-        :  link fields’ soft mass;
- MSSM gaugino mass:
-      at tree-level from the mixing of A and B gauge groups
-     In the limit mB « M
-     (M: heavy gauge boson masses)

## MSSM soft scalar masses: one-loop w/ gauge multiplets and the link fields and soft mass insertions.

            Gaugino loop                                           Link field loop   
To have EWSB, must consider a negative 2-loop top-stop-gluino contribution to soft masses of Hu.

-             Gaugino loop                                           Link field loop
- To have EWSB, must consider a negative 2-loop top-stop-gluino contribution to soft masses of Hu.

## Sample Spectrum

    LSP: Gravitino
    NLSP:  τ̃R
  NNLSP’s: 
   Left-handed sleptons

(Similar spectrum has been obtained
through warped 5D constructions: 
Chacko, Ponton 03’; 
Medina, Wagner 06’)

-     LSP: Gravitino
-     NLSP:  τ̃R
**  ****NNLSP’s: **
**   ****Left-handed sleptons**
- (Similar spectrum has been obtained
- through warped 5D constructions:
- Chacko, Ponton 03’;
- Medina, Wagner 06’)

## Decay chains

## Cross section for squark pair production and interesting final states with multi-leptons and Higgses at the LHC; each final state includes 2j+2 stable charged tracks.

## Conclusions and future directions

-  Lg̃̃̃M  predicts that sfermions much lighter than gauginos;
-     Hallmark of  Lg̃M is that both left- and right- handed sleptons are lighter than all other sparticles except the gravitino.
- Study of the different signatures and the searching strategies.
- Distinguishing from other models with similar spectrum: Dirac gaugino model (“supersoft models” Fox, Nelson and Weiner 02’) ;
-     GMSB w/ a large number of messengers (>30) ...
- Model building issues: generate the scale dynamically; mu/Bmu; gauge coupling unification.