# Presentation: 000307

## Maximal Flavor Violation

**based on work in:**** 1. ****arXiv/0711.3193  **** ****AR & Shaouly Bar-Shalom**** ****2. ****arXiv/0803.3795**** **** ****AR, Daniel Whiteson, Felix Yu  & Shaouly Bar-Shalom**** **

**Arvind Rajaraman**
** ****University of California, Irvine**

## The “New Physics Flavor puzzle” & MFV

- The** **hierarchy problem, dark matter, unification, EWSB ...** **
-     The SM is incomplete – **need new physics at TeV scale**
**The NP favor puzzle:** given new particles at the TeV scale, why does the NP not induce LARGE flavor violating dynamics?
- Traditional solutions:
**M(new particles) > 10-100 TeV**            (somewhat in conflict with e.g., the hierarchy problem, dark matter)
**Impose FV(new particles) very small; e.g. use MFV ansatz.**

## MFV (Minimal Flavor Violation)

**A**ll flavor violation is “aligned” with the SM i.e. all sources for FV are governed solely by the SM’s Yukawa interactions and are hence proportional to the small off-diagonal CKM elements (Ambrosio, Giudice, Isidori, Strumia (NPB645, 2002) )

## (

-  (uij  uRiQLj +  (dij  dRiQLj.

- Minimal flavor violation implies that

- u

- d ~ Md

-  √2

- __

- v

- ~  Mu

-  √2

- __

- v

- 0 0 0
- 0 0 0
- 0 0 1

- )

- ~

- 0 0 0
- 0 0 0
- 0 0 0

- )

- ~

- _

- _

- MFV (Minimal Flavor Violation)

## MFV (Minimal Flavor Violation)

**The MFV ansatz is  useful for satisfying constraints from low-energy flavor data, e.g. meson mixings**
**BUT: is it necessary ? **
**Can we have O(1) flavor transitions (e.g., charged t********d, b ********u or neutral t********u or both!)  and still satisfy those constraints?**

## Motivation - Why go beyond MFV

** ****MFV only an ansatz;**** ****                    has not been tested so far except in low-energy FCNC**** **
** ****Should look for all possibilities;****                    may help in constructing models extending the SM**** **
** ****Most important;**** ****                    we may overlook/miss important signals at colliders****                    which are not predicted by MFV models ...**

## (

- u

- d

- 0 0 a
- 0 0 0
- c 0 0

- )

- ~

- 0 0 0
- 0 0 0
- 0 0 0

- )

- ~

- Maximal flavor violation-1

- u

- d

- 0 0 0
- 0 0 b
- 0 d 0

- )

- ~

- 0 0 0
- 0 0 0
- 0 0 0

- )

- ~

- Maximal flavor violation-2

- or

- Bar-Shalom, AR

- MxFV (Maximal Flavor Violation)

## MxFV (Maximal Flavor Violation)

**Maximally departing from MFV** (in flavor space):

** ****MxFV ******** O(1) non-diagonal CKM physics  ~**

** ****MFV ******

- Compare

## Models of MxFV (cont.)

- Not difficult to construct realistic models where, e.g.,

******31 ****, ********32 ****~ V****tb  ****>>  ********33 ****~ V****td **

## Models of MxFV (cont.)

-  IF **Z****2****(MxFV)** is exact then:

**When Z****2****(MxFV) is weakly broken** (as we expect it to be e.g., by a very       small ******FV **condensate or by higher dimensional operators) then a very small value for the CKM elements **V****td ****, V****ts ****, V****ub ****, V****cb****  ****as well as **for all zero entries in **** are generated.
**We thus expect (after Z****2****(MxFV) breaking):**                                     **e.g.** ******33** ~ **V****td ****, V****ts****  ****while maintaining ********31 ****, ********32 ****~ V****tb ****~ O(1)**

**with** ******ij** ~ **V****ij ****~ O(1)**** **

## Models of MxFV (cont.)

**after Z****2****(MxFV) breaking we expect e.g.:****                                                  ******** ********+ ****td , ********0 ****tu ~ V****tb****  **

## Experimental constraints

- Are these viable textures? After all, they do not follow MFV.
- e.g. kaon mixing could be problematic.

- d

- s

- But in the first  texture,  there is only a coupling between the
- first and third generations, and in the second, there is only a
- coupling between the first and third generations.
- In either case, the diagram vanishes. No constraints.

## Experimental constraints on MxFV

**ALL O(1) ****single-coupling**** textures are viable:**

** ****Constraints apply only to the following  MxFV coupling products:**

## Experimental constraints (cont.)

**Only constrains the product ********32****  ********31.**** **

## The Viable MxFV coupling products

**The Viable MxFV coupling products**

**m******** [GeV]**

******+ only**

******+ only**

## Collider signatures of MxFV1

**Collider signatures of MxFV****1**

**i.e.  from O(1)**

**Leads to a very well defined set of processes that basically fall into 4 categories:**
**t********FV**** ****production**
******FV********FV**** ****production**
**s-channel ********FV ****resonance**
**t-channel ********FV ****exchanges**

## 1. tFV production:

**j = light quark (u or d) jet**

**2. ********FV ********FV ****production:**

## 3. s-channel FV resonance:

**No  resonance production of**** ********0**** .**
**Resonance production of **** ********+****  ****via either the 1-b tag or 2-b tag ****	****	****processes: **** **** **

**leads to a resonance peak in the invariant mass of the  t+j pair **

## 4. t-channel FV exchanges:

## Collider signatures of MxFV

- 1. Enhanced production of a “charged Higgs” in association with a top or a bottom quark:

**i.e. enhanced mainly by a factor of ****[****PDF(d or u)****/****PDF(b)****]**** ****over MSSM and MSSM-like Higgs sectors **
**e.g.,  at the LHC**

**if ********~1  &  ****m****H+**** ,**** ****m********+ ****~ 200 GeV****!**

## Collider signatures of MxFV

**i.e. enhanced over MSSM and MSSM-like Higgs sectors****by a factor of  ****(for ********~1)**

**Collider signatures of MxFV**

## Collider signatures of MxFV

**A. Rajaraman, D. Whiteson, F. Yu & SBS , arXiv/0803.3795**

**Collider signatures of MxFV**

**When both tops decay leptonically (t********bW ********bl********), this leads to a **
**striking low background signature of **
**same-sign leptons + missing energy + b-jets**

## Same-sign leptons from same-sign tops at the Tevatron

**Define the inclusive same-sign top reaction:**

-                reacll the underlying hard processes:

**Yielding (after both tops decay leptonically) the same-sign lepton signature:**

## # of expected signal events at CDFII :

**# of expected ****signal**** events at CDFII :**

**Total expected:**

## # of expected background events at CDFII :

**background estimated using simulated events with ALPGEN, showering modeled by PYTHIA and CDFII response by CDFSIM  **

**background from diboson production ZZ,WZ,W********,Z********  is essentially eliminated by the requirement of a b-tag. **

## Observed

## Tevatron bounds on MxFV

## If  ~1 & m0 ~  200 GeV, expect 10000 events with

**If ******** ~1 & m********0 ****~****  ****200 GeV****, expect 10000 events with**
**10/fb luminosity. **
**Background 2500 ****±**** 500 events.**
**Work in progress.**

## Summary & outlook

** ****Fairly easy to construct such models.**

**Summary & outlook**

** ****Leads to surprising new phenomenology e.g., same-sign leptons  **
**from same-sign tops at hadron colliders**
** ****Unfortunately, no signal found at the Tevatron.**

## Summary & outlook

**Summary & outlook**

-  **Several other interesting signatures: e.g., enhanced t-H+ **
**production & new H+ resonance channels.**