Download presentation

Presentation is loading. Please wait.

Published byMacy Jessel Modified over 3 years ago

1
Rare B Decays Chris Parkes SUPA Postgraduate Lectures Introduction Radiative decays b s b d Electroweak Penguin b sl + l - Rate Forward backward asymmetry Final states with neutrinos

2
B mesons / Baryons Masses known to a few MeV and various excitations Baryons In spectator model b lifetimes would all be the same –Non-spectator effects give rise to a hierarchy Theory and experimental pattern in agreement Evidence 1998 Accurate Mass 2005

3
What do we mean by a rare B-decay ? All decays ‘rare’ as decays out of generation Flavour Changing Neutral Currents (FCNC) are even more suppressed as forbidden at tree level in SM –b s –b d Rare in this context means not b c

4
Feynman Diagrams for B Processes

5
FCNC B decays Forbidden at tree level in SM Occur via Penguin / Box diagrams Sensitive to New Physics heavy particles –SUSY, non-SM Higgs

6
Operator Product Expansion (OPE) A method of formulating an effective theory of the interaction Feynman diagram full process description Or Effective point-like vertex e.g. decay Contains : 1)CKM elements V CKM 2)Matrix Element Operators non-perturbative - Lattice Calculations, HQET 3)Wilson Coupling Coefficients C i (there are 10) Aim to measure these – sensitive to new physics Form an effective weak Hamiltonian, effective vertices multiplied by effective coupling constants

7
bsbs

8
Discovery of b s , B K* FCNC CLEO, 1993 (PRL 71,674) Later extended to inclusive b s rate measurement Rate sensitive to new physics

12
Current Result (BaBar/Belle)

13
bdbd

15
Discovery of b d

16
And… b d gluon (g )

20
Forward Backward Asymmetry of leptons sensitive to New Physics, determine C 7 C 9 C 10

21
Determined with low precision Requires a larger data sample LHCb or Super-B Factory

22
Channels with neutrinos

26
B (s) + -

27
Really really rare! SM box SM Penguin Sensitive to New Physics in SUSY models

28
B (s) + - Unique Experimental signature Easy to identify / trigger – good for ATLAS/CMS Really really rare! Needs LHC data sample for SM B s 3.5x10 -9, B d 1.0x10 -10 Current limits from Tevatron

29
Information Sources Varenna CP violation school 2005 –http://varenna05.pi.infn.it/ –Slides taken from talks of: –Rare B Decays – H. Aihara OPE & Wilson Coefficients, A. Buras hep-ph/9806471

Similar presentations

OK

2 Challenging Reveal physics beyond the Standard Model Unique opportunity to measure Standard Model parameters Precision test of the Standard Model “New.

2 Challenging Reveal physics beyond the Standard Model Unique opportunity to measure Standard Model parameters Precision test of the Standard Model “New.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on power sharing in democracy Ppt on biodegradable and non biodegradable materials Ppt on water conservation in hotels Ppt on sources of energy for class 8th Ppt on power system stability study Ppt on ca student life Ppt on area of parallelogram and triangles and quadrilaterals Ppt on electron spin resonance spectroscopy Pdf to ppt online Ppt on switching network device