B Factory B Factory Measurements of the Measurements of the bs(d) s(d) “Radiative Penguin” “Radiative Penguin” Transition Rates Transition Rates for the BaBar and Belle Collaborations Miami 2008 Topical Conference on Elementary Physics, Astrophysics, and Cosmology Fort Lauderdale, FL, Dec 16- 21, 2008 Bruce A. Schumm Santa Cruz Institute for Particle Physics University of California, Santa Cruz BaBar
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For the BaBar and Belle Collaborations Miami 2008 Topical Conference on Elementary Physics, Astrophysics, and Cosmology Fort Lauderdale, FL, Dec 16-21,
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B Factory Measurements B Factory Measurements of the bof the b s(d) s(d) “Radiative “Radiative Penguin” Transition RatesPenguin” Transition Rates
for the BaBar and Belle Collaborations
Miami 2008 Topical Conference on Elementary Physics, Astrophysics,
and Cosmology
Fort Lauderdale, FL, Dec 16-21, 2008
Bruce A. SchummSanta Cruz Institute for Particle Physics
University of California, Santa Cruz
BaBar
Miami 2008: b s(d) Transition Rates 2Bruce SchummBaBar
OutlineOutline
Effective Neutral Currents: General Motivation
b s PenguinsSUSY parameter space implications
b s “Inclusive” approach
B XS “Semi-Inclusive” approach
b d Penguins and |Vtd/Vts|
Motivation
B →(ρ,ω)“Exclusive” approach
B→Xd “Semi-Inclusive” approach
Status of |Vtd/Vts|
Conclusions
Miami 2008: b s(d) Transition Rates 3Bruce SchummBaBar
Effective Neutral Currents and Radiative PenguinsEffective Neutral Currents and Radiative Penguins
so new physics can enter at leading order:
The SM b s(d) transition is high order (two weak plus one EM vertex) …
+ photon off any charged
leg
Although rare (~ 5x10-4 for s and ~10-5 for d), the isolated high-energy photon is a powerful signature.
Vtb Vt(s,d)
Miami 2008: b s(d) Transition Rates 4Bruce SchummBaBar
OutlineOutline
Effective Neutral Currents: General Motivation
b sSUSY parameter space implications
Inclusive approach
Other approaches
b d and |Vtd/Vts|
Motivation
B →(ρ,ω)(“Standard” Approach)
B→Xd (“Semi-Inclusive” Approach)
Status of |Vtd/Vts|
Conclusions
Miami 2008: b s(d) Transition Rates 5Bruce SchummBaBar
B B s s and SUSY Parameter Space and SUSY Parameter Space
Direct searches (LEP)
B s constraints
MSSMConstraints
bs has a significant impact on the tan-mA plane…
Miami 2008: b s(d) Transition Rates 6Bruce SchummBaBar
B B s s and SUSY Parameter Space (cont’d) and SUSY Parameter Space (cont’d)
Fate of “Snowmass” MSSM study points
… on some of our favorite scenarios …
Miami 2008: b s(d) Transition Rates 7Bruce SchummBaBar
B B s s and SUSY Parameter Space (cont’d) and SUSY Parameter Space (cont’d)
“New” Approach (BaBar): Reconstruct seven exclusive final states Xd in range 0.6 GeV/c2 < MXd < 1.8 GeV/c2
Miami 2008: b s(d) Transition Rates 24Bruce SchummBaBar
Measured Regions for B Measured Regions for B X Xd(s)d(s)
(,,K*) 1.0 < Mhad < 1.8 1.8 < Mhad
XS
Xd
MEASURED
UNMEASURED
and Xd analyses
Xd analysis only
Mhad (MXd)
# 0
# bodies
Miami 2008: b s(d) Transition Rates 25Bruce SchummBaBar
B B X X(s,d)(s,d) Partial Branching Fraction Results Partial Branching Fraction Results
Fit in high-mass Xd region (first time measured):
Yields and partial branching fractions:
High-mass b
Xd
Continuum background
Xs, MisID background
BABAR
BABAR
PRELIMINARY
Miami 2008: b s(d) Transition Rates 26Bruce SchummBaBar
Correction for Missing ModesCorrection for Missing Modes
Dominant systematic error for 1.0 < MX < 1.8 GeV/c2
Most difficult for B Xd (not constrained by data)
Can improve with statistics (internal constraints)
Errors: Statistical Experimental Systematic
Try several models:
• MX given by “KN Model” Kagan & Neubert, Phys. Rev. D 58,
094012 (1998), with phase-space fragmentation
• As above, but with 50% replaced by mix of resonances
• Fix to measured b s fragmentation
Primary experimental result
BABAR
PRELIMINARY
Miami 2008: b s(d) Transition Rates 27Bruce SchummBaBar
Ratio of Total Widths and |VRatio of Total Widths and |Vtdtd/V/Vtsts||
arXiv:0807.4975 [hep-ex]; submitted to PRL
Precise (~1%) expression for |Vtd/Vts| [Ali, Asatrian, Greub] is based on ratio of full widths (bd)/(bs)
Measured region 0.6 < MX < 1.8 is ~50% of width
Extrapolate to full mass region via “KN Model”; KN calculation suggests negligible difference and uncertainty in extrapolation of the ratio (because ms,md << 1.8 GeV/c2?)
Ali
Asatrian
Greub
)(
)(
sb
db
009.0013.0033.0
|/|tstdVV
001.0043.0177.0
Expt. Theory
BABARBABAR PRELIMINARY
PRELIMINARY
Miami 2008: b s(d) Transition Rates 28Bruce SchummBaBar
Global Status of |VGlobal Status of |Vtdtd/V/Vtsts||
No evidence for non-Standard Model contribution to the decay width.
*
PRELIMINARY*
Miami 2008: b s(d) Transition Rates 29Bruce SchummBaBar
Concluding RemarksConcluding Remarks
Radiative measurements of |Vtd/Vts| are becoming precise:
| Vtd/Vts|rad = 0.203 0.020
Semi-inclusive approach works, and is independent of exclusive approach, with small theoretical uncertainty
Agreement with SM (as constrained by B mixing) is good
In principle, the severe SM suppression of this radiative process (x10-6 of B mixing) should make it very sensitive to new physics contributions.
Have we fully thought through the meaning of this constraint?
B s continues to be leading constraint on MSSM parameter space
More data exists (~80% of BaBar sample) to improve measurement, but “inclusive” approach starting to be limited by difficult systematics
“Semi-inclusive” approach has systematics independent of inclusive approach; very little of existing sample has been analyzed in this way.
Miami 2008: b s(d) Transition Rates 30Bruce SchummBaBar
Backup Slides
Miami 2008: b s(d) Transition Rates 31Bruce SchummBaBar