Rare Semileptonic B-decays at LHCb

Rare Semileptonic B-decays at LHCb

Marko Zupan

Overview

bullBrief look at formalism

bullObservables of rare semileptonic B-decays

and their significance

bullExperimental status

bullLHCb performance in the reconstruction of

rare semileptonic B decays ndash Patrick

Koppenburg

bullStatus of my analysis

OPE Terms for Weak Decays

eff i ii

A M F F H M C F Q M

bullCurrent-Current Operators Q1 Q2 Qu1 Qu

2

bullQCD Penguin Operators Q3 Q4 Q5 Q6

bullElectroweak Penguin Operators Q7 Q8 Q9

Q10

bullMagnetic Penguin Operators Q7g Q8G

bullSemileptonic Operators Q9V Q10A Qnn Qmm

Relevant Penguin Operators for FCNC Decays

7 216 b R q L

eQ q m P m P b F

9 216V L

eQ q P b l l

10 5216A L

eQ q P b l l

Magnetic penguin operators

Semileptonic penguin operators

8 216a aS

G b R q L

gQ q T m P m P b G

The Effective Hamiltonian

6

7 7 8 8

12F

eff ts tb i i G Gi

GH b s V V C Q C Q C Q

9 9 10 10

2F

eff eff ts tb V V A A

GH b lls H b s V V C Q C Q

7 7 5 6

1

3effC C C C 9 9

effV VC s C Y s

Decay Amplitudes

9

10 5

7

2

2

[

]

effF Sts tb V L

A L

effb R

GM b lls V V C s P b l l

C s P b l l

qm C si P b l l

s

non perturbativesM B llX M b lls

b rarr s Decays

9VQ 10AQ

bullbrarrsll allow measurement of C7 C9V C10A

bullbrarrs sensitive to |C7|

Dilepton Mass Distributions

Hadron Mass Distributions

Forward-Backward Charge Asymmetry

1 02 2

0 11 2

1

cos coscos cos

coscos

d BR d BRd d

d ds d dsA s

d BRd

d ds

b s

-

+

Forward-Backward Charge Asymmetry

29 0 0

2 27 0 0

2effV b Beff

B K

C s m m s

C s m m s

s0 is stable against form factor modelling within SM

CP Violation

B BFBCP B B

A s A sA s

A s A s

10 9

10 9

effA VFB

CP effA V

C CA

C C

max

min

10

10

003 001s

AFBCP

As

CA s ds

C

22min max 145 B Ks GeV s m m

CKM contribution O(10-3)

CP Violation Measuring |Vtd| |Vts|

max

min

sq

q

s

dBR B llXBR ds

ds

2 2min max10 60s GeV s GeV

1

2q q qBR BR BR

2

2td d

sts

V BR

BRV

Beyond the Standard Model

bullAbsolute values of Wilson coefficients modified

bullNew complex phases for Wilson coefficients

bullNew operator basis

bullCKM model may not hold

Experimental Results

Belle BrarrK 099 10-6

Belle BrarreeK lt 13 10-6

BaBar BrarrllK lt 050 10-6

Belle BrarrK lt 31 10-6

Belle BrarreeK lt 56 10-6

BaBar BrarrllK lt 29 10-6

D0 brarrq lt 32 10-4

Belle BrarrXs lt 191 10-6

Belle BrarreeXs lt 101 10-6

Branching Ratios at 90 CL

LHCb Performance Dilepton Mass Distribution

Inclusive channel dimuon mass distribution after one year of data taking

LHCb Performance Hadron Mass Distribution

Inclusive channel hadron mass distribution after one year of data taking

LHCb Performance Forward-Backward Asymmetry

Forward-backward charge asymmetry after one year of data taking

BrarrK

BrarrK

LHCb Performance Measuring |Vtd| |Vts|

Relative uncertainty on after one year and five years of data taking |Vtd| |Vts|

Status of my analysis

Where are all the Bs

Status of my analysis (2)bullFind muon vertex

bullcut on

bull pt

bull impact parameter to primary vertex

bull dimuon mass

bull vertex 2

bull Find and vertex combinations of kaons and pions Xs

bull K

bull K

bull K

bull K

Status of my analysis (3)bullFrom dimuon and kaon-pion combinations reconstruct B-vertex

cut on

bull impact parameter with respect to PV

bull impact parameter of Xs on dimuon

bull vertex 2

bull charge of Xs

bull B mass

Status of my analysis (4)

bull Analysis done with Bender (v1r0) ndash

a Python wrapper of LoKi

bull Problems accessing MC truth information

bull Unclear binding to DaVinci algorithms and settings

bull Ease of use justifies ldquogrowing painsrdquo

bull Any commentadvice welcome