# Presentation: 636451

## Introduction

-   In the Standard Model, the FCNC decay of B +- is heavily
-    suppressed

-   SM prediction is below the sensitivity of current experiments
-    (CDF+D0):  SM   Expect to see 0 events at the Tevatron
-               **Any signal would indicate new physics!!**

- (Buchalla & Buras, Misiak & Urban)

-   Bd is further suppressed by CKM couping (vtd/vts)2

- SM prediction 

- Cheng-Ju Lin   Fermilab Wine&Cheese

## Would be observable at the Tevatron

_**BEYOND STANDARD MODEL**_

-   In many SUSY models, the BR could be enhanced by many
-    orders of magnitude:

- For example:
-      -  MSSM:  Br(B) is
-          proportional to tan6
- 
-     -  Br(B ) also
-        enhanced at high tan in
-        GUT SO(10) models
- BR could be as large as
-          10-1000 times the SM prediction

- Cheng-Ju Lin    Fermilab Wine&Cheese

## Would also be observable at the Tevatron

****

******

********’****i23**

********i22**

****

****

***b***

***s***

**      ****R-parity violating SUSY**

-   Another example:
-    R-Parity violating SUSY
-        - Tree level diagram is allowed in
-          R-parity violating (RPV) SUSY
-          models.
-         - Possible to observe decay
-           even for low value of tan
-        -  Enhancement depends strongly
- on coupling constants (’

- Cheng-Ju Lin    Fermilab Wine&Cheese

## PROBE OF NEW PHYSICS

-    New physics may enhance Bs and
-      Bd differently
-    Minimal-flavor-violation (MFV)
-      assumption in SUSY yields SM
-      relations between Bs and Bd
-  decays
-    Can observe both Bs and Bd: unique to
-      Tevatron
-   CDF has the mass resolution to
-     distinguish two decays, M~23MeV :
-     unique to CDF
-   Either observation or null search, results will provide important
-    clues about possible scenarios of new physics beyond SM

- M(Bs)-M(Bd)~90MeV

## Limits Summary

-                           **1.6**×10-7** @ 90% CL **
**                          ****2.1**×10-7** @ 95% CL**
- Bd: we observed 0 events which yields a combined limit of:
-                           **3.9**×10-8** @ 90% CL **
**                          ****5.1**×10-8** @ 95% CL**
-          Br(Bs) < 4.1×10-7 @ 90% CL ;  D0 PRL 94 (2005) 042001
-          Br(Bs) < 5.8×10-7 @ 90% CL ; CDF PRL  93 (2003) 032001
-          Br(Bd) < 3.0×10-7 @ 90% CL ; D0 Preliminary 4733
-          Br(Bd) < 8.0×10-8 @ 90% CL ; (BaBar PRL 94 (2005) 221803
- Both CDF Bs and Bd results are x2 better than the best published result!!!

_**Limits Summary**_

## RPV SUSY EXCLUSION

-   Possible to exclude phase space
-    even for small tan()
-   Exclusion strongly depends on the
-    coupling.

- Excluded

## mSUGRA  M0 vs M1/2

-   We are beginning to carve
-     into mSUGRA space
-   For mh~115GeV implies
-    10-8<Br(Bs)<3×10-7

- Solid red = excluded by theory or experiment
- Dashed red line = light Higgs mass (mh)
- Dashed green line = (a)susy  (in units of 10-10)
- Black line = Br(Bs)

- M0 [GeV]

- Excluded

- Excluded

## Excluded by this

-   We are beginning to carve
-     into mSUGRA space
-   For mh~115GeV implies
-    10-8<Br(Bs)<3×10-7

- Solid red = excluded by theory or experiment
- Dashed red line = light Higgs mass (mh)
- Dashed green line = (a)susy  (in units of 10-10)
- Black line = Br(Bs)

- M0 [GeV]

- Excluded

- Excluded

- new result

## SO(10) Unification Model

**hep-ph/0304101**

_**SO(10) Unification Model**_

-  tan()~50 constrained by
-   unification of Yukawa coupling
-   White region is not excluded
-  Unification valid for small M1/2
-   (~500GeV)

- Red regions are excluded by either theory or experiments
- Green region is the WMAP preferred region
- Blue dashed line is the Br(Bs) contour
- Light blue region excluded by old Bs analysis

- h2>0.13

- m+<104GeV

- mh<111GeV

## SO(10) Unification Model

**hep-ph/0304101**

_**SO(10) Unification Model**_

-  tan()~50 constrained by unification
-   of Yukawa coupling
-  All previously allowed regions (white)
-   are excluded by this new measurement
-  Unification valid for small M1/2
-   (~500GeV)
-   New Br(Bs limit strongly
-    disfavors this solution for
-    mA= 500 GeV

- Red regions are excluded by either theory or experiments
- Green region is the WMAP preferred region
- Blue dashed line is the Br(Bs) contour
- Light blue region excluded by old Bs analysis

- h2>0.13

- m+<104GeV

- mh<111GeV

- Excluded by this
- new result

## Bs Limit Projection

-   Extrapolate based on the
-    current analysis which was
-    optimized for 1/fb
-   Assume background scales
-     linearly with luminosity
-   Will need to re-optimize the
-    analysis for > 3/fb

- Cheng-Ju Lin    Fermilab Wine&Cheese