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Hadronic B Decays To Double-Charm Final States. SERGIO GRANCAGNOLO L.Lanceri – J.P.Lees BINP Novosibirsk Particle Physics Seminar. Outline. Introduction The BaBar Detector at PEP-II The D sJ observations Theoretical Interpretations of D sJ Analysis of B D (*) D sJ decays

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Hadronic b decays to double charm final states

Hadronic B DecaysTo Double-Charm Final States

SERGIO GRANCAGNOLO

L.Lanceri – J.P.Lees

BINP Novosibirsk

Particle Physics Seminar


Outline
Outline

  • Introduction

  • The BaBar Detector at PEP-II

  • The DsJ observations

  • Theoretical Interpretations of DsJ

  • Analysis of BD(*)DsJ decays

  • Results: branching fractions and angular distributions

  • Comparison with models and conclusions

Sergio Grancagnolo



The standard model
The Standard Model

  • Fundamental particles:

    • 6 quark , 6 leptons

    • 4 interactions

  • The model works well but there are several issues to be understood, for instance:

    • Higgs boson

    • Supersymmetry

    • Strong interactions

W,Zbosons

Sergio Grancagnolo


Quantum numbers of the quarks
Quantum Numbers Of The Quarks

Quark

Property

Sergio Grancagnolo


Ckm matrix and unitary triangle
CKM Matrix and Unitary Triangle

qi=u,c,t

Unitary relationship

CKM

W+

Vij

qj=d,s,b

A complex phase in the V matrix can be a source of CP violation in B decays

VV†=I

VudVub*+VcdVcb*+VtdVtb*=0

a

VtdVtb*

VudVub*

Unitary triangle

g

b

VcdVcb*

Sergio Grancagnolo


Mesons in the quark model

_

_

_

_

_

Mesons in the Quark Model

  • Quarks exist only in baryons and mesons

  • Mesons are made of a quark-antiquark pair

  • As an example:

  • Mesons are not stable

    • Mass, charge and lifetime are main characteristics

    • Meson width~ 1/lifetime

      depends on the allowed decay modes

Sergio Grancagnolo


Heavy quark approximation

sQ

sq

q

_

Q

Heavy Quark Approximation

In the heavy quark approximation

mq<<mQ,, mQ

sQ, j conserved

However J, P good quantum numbers

Sergio Grancagnolo


Charmed mesons spectroscopy
Charmed Mesons Spectroscopy

_

_

  • States with ℓ=1 can decay strongly with emission of a pseudoscalar meson

    • j=1/2 emission in s-wave

    • j=3/2 emission in d-wave

  • D*0,D´1observed by CLEO, Focus and Belle

    • Broad resonances as expected

ℓ=0

ℓ=1

broad ~100 MeV

narrow ~10 MeV

Sergio Grancagnolo


The expected cs meson spectra

_

The expected cs Meson Spectra

M.Di Pierro, E.Eichten

Phys. Rev. D64, 114004 (2001)

2.51 GeV

2.36 GeV

States expected but not observed

  • Masses over threshold DK(*)

  • Broad states (large widths)

*

Sergio Grancagnolo


B meson decay
B Meson Decay

  • Spectator quark model

    the other u,d quark enters the final state without participating to the interaction

  • In hadronic decays, could be tested the factorization hypothesis:

    the final hadrons are produced independently

Since

mb >>mu,d

the B meson decay dominantly through

the disintegration of the b quark. The main transition

W* ℓn

semileptonic

is the weak decay

bcW*

where

_

hadronic

W* qiqj

W* virtual boson

Sergio Grancagnolo


Exclusive hadronic b decays

_

-

_

_

_

_

Exclusive Hadronic B decays

  • In exclusive decays all particles in final state are reconstructed

  • Double charm decays contains two mesons with charm quarks

  • Examples:

Ds-

BDsD

_

D(*)0,D(*)+

B-,B0

D(*)0

K(*)-

B DDK

B-,B0

D(*)0,D(*)+

Sergio Grancagnolo



The pep ii b factory at slac
The PEP-II B-factory at SLAC

PEP-II is a high luminosity, asymmetric, e+e- collider

Integrated luminosity

Lint=254 fb-1

113fb-1

Ldesign = 3 x 1033 cm-2s-1

Lpeak = 9.21 x 1033 cm-2s-1

Sergio Grancagnolo

year


B factory cross sections
B-factory Cross Sections

E(e+) = 3.1 GeV E(e-) = 9.0 GeV

The boost allows a separation of the two B vertices.

boost: bg=0.56

Ecm=10.58 GeV

_

_

U(4S)BB

_

_

_

s[e+e- hadrons](nb)

_

√s(GeV)

_

_

e+e- bb on-resonance BB

_

“coontinuum”e+e- cchigh momentum charmed particles

Sergio Grancagnolo


Babar detector
BABAR Detector

1.5 T solenoid

Electromagnetic Calorimeter

e+ (3.1 GeV)

Cerenkov Detector (DIRC)

e-(9 GeV)

Drift Chamber

Silicon Vertex Tracker

Instrumented Flux Return

Sergio Grancagnolo


The d sj observations

The DsJ observations


D sj 2317 discovery
DsJ(2317) Discovery

*

+

  • BaBar discovered a new particle decaying into Dsp0

    • c and s quarks

    • Mass < DK threshold

    • Width < 10 MeV

  • Seen by Belle and CLEO

  • Is this the expected Ds0?

BaBar collaboration

Phys.Rev.Lett.

90, 242001 (2003)

+

_

Dsp0Invariant mass

+

*+

m=2.317GeV

GeV

Inclusive selection of high momentum charmed meson from coontinuume+e- cc

_

Sergio Grancagnolo


D sj 2460 discovery
DsJ(2460) Discovery

+

  • CLEO observed another state decaying to Ds p0!

    • c and s quarks

    • Mass < (DK)* threshold

    • Width < 10 MeV

  • Observed also decay modes:

    • Dsg, Dsp+p-

  • Is this the expected Ds1?

CLEO collaboration

Phys. Rev. D68, 032002 (2003)

*+

_

Ds p0Invariant mass

*+

80

60

m=2.460 GeV

Events/7 MeV/c2

40

20

0

+

+

2.25 2.5 2.75

GeV

+

Seen by BaBar and Belle

Sergio Grancagnolo


The observed cs meson spectra

_

The Observed cs Meson Spectra

2.51 GeV

2.36 GeV

New states observed

  • Masses below threshold DK(*)

  • Narrow states

*

Sergio Grancagnolo


Isospin violation in these decays
Isospin Violation in These Decays

  • Isospin symmetry is not exact

  • Violation already observed in Ds* Dsp0 decay

_

_

_

_

_

_

_

DsJ Dsp0

Invoked hp oscillation

P.L.Cho, M.B.Wise Phys.Rev.D49: 6228-6231,1994

Sergio Grancagnolo


Theoretical interpretations of d sj

Theoretical Interpretations of DsJ

Standard interpretations

Exotic interpretations


Standard interpretations
Standard interpretations

Entia non sunt multiplicanda praeter necessitatem (G.Occam)

  • Quark models

    • Potential: coulombian

  • (0-,1-),(0+,1+) chiral partners

    • doublets mass splitting via chiral symmetry breaking

    • transitions via scalar meson

+ linear

Cahn, Jackson

+ spherical not linear

Lucha, Schoberl

need to adjust a posteriori input parameters, predict mass higher than observed or not reproduce non-strange charmed mesons spectra

Bardeen, Eichten, Hill

hyperfine splitting for charmed mesons (D, D*, etc.) marginally compatible with experiments

Sergio Grancagnolo


Standard interpretations1
Standard interpretations

  • Unitarized chiral models

    • generalization replacing a light quark with an heavy quark

  • Non-perturbative methods

    • lattice QCD

    • QCD sum rules

Beveren, Rupp

several new mesons predicted not observed

Bali

initial difficulties to reproduces masses, reproduces mass splitting

Dai, Huang, Liu, Zhu

low accuracy

Sergio Grancagnolo


Exotic interpretations

D

K

Ds

p

Exotic Interpretations

Barnes, Close, Lipkin

Dsp molecule

cs  DK  4-q

mixing

DK molecule

Szczepaniak

Browder, Pakvasa, Petrov

D

_

_

_

_

qq

qqqq

K

di-quark pairs

_

qq

Maiani, Piccinini, Polosa, Riquer

_

qq

Sergio Grancagnolo


Analysis of b d d sj decays

Analysis of BD(*)DsJ decays

Branching ratios: Method

Event selection

Signal and Backgrounds

Efficiency and “cross-feed”


B d d sj decays
BD(*)DsJ Decays

  • ExclusiveDsJ production: expected to be dominant

  • Allow to measure DsJquantum numbers

  • In principle, allow to discriminate between conventional and multi-quark scenarios compared with other B decays such as BD(*)Dsand BD(*)D(*)K

  • If the DsJ is the conventional cs state should be produced in the following graph:

_

_

Weak external W emission

DsJ-

-

_

_

_

_

_

D(*)0,D(*)+

B-,B0

Same graph as BD(*)Ds

similar branching ratios could be expected

Sergio Grancagnolo


B d d sj decays ii
BD(*)DsJ Decays (II)

  • We search for DsJ particles looking at the 12 combinations:

  • With DsJ decays:

  • We measure branching ratios, quantum numbers JP

Sergio Grancagnolo


Subdecay modes
Subdecay Modes

Intermediate particles are reconstructed in the following modes:

Green::clean modes

Total: 60 different submodes combined to give the 12 combinations

Sergio Grancagnolo


Analysis goal and method
Analysis Goal and Method

  • We aim to measure branching ratiosBri (i=1…12) of the exclusive double charm two body production of DsJ(2317)+and DsJ(2460)+in B0and B+

  • nisignumber of signal candidates for mode i

    • after combinatorial background subtraction

  • nixfdnumber of crossfeed events for mode i

    • contains background from other signal modes

  • eireconstruction efficiency from simulation

  • NBB= [122.0 ± 0.6(stat) ± 1.3(syst)]  106 (113 fb-1)

*

_

Sergio Grancagnolo


A specific example b 0 d d sj 2460

_

D0

Ds

+

DsJ(2460)+

*

A specific example: B0D*-DsJ(2460)+

*

  • Reconstruct the chain:

  • Reconstruct tracks (K,p) and photons (g)

  • Select D0, Ds , f, p0computing invariant masses

  • Use beam energykinematicconstraint

  • Fit nisig in Dsg invariant mass distribution

K+

K+

p-

f

D*-

p-

K-

p+

B0

g

Sergio Grancagnolo


Event selection invariant masses
Event Selection: Invariant Masses

Invariant mass:

D0 Kp

Dsfp

D* D0p

fKK

40000

20000

0

0.99 1.02 1.04

m(f)(GeV/c2)

Particles masses are set to their nominal values (mass constraint)

Sergio Grancagnolo


Event selection b candidates
Event Selection: B candidates

  • Compute p*B and E*Bfrom selected D*, Ds, g

  • Use the B-factory constraint E*beam to compute:

5.272<mES<5.288 GeV

mES

“Signal box”:

|DE|<32MeV

Use of beam kinematic variables

better resolution

ΔE

uncorrelation

Sidebandsto estimate background outside signal box

Sergio Grancagnolo


D e resolution
DE resolution

  • Same resolution for all the submodes

  • A systematic error will take in account differences between data and simulation

Simulation of signal events

Data candidates in mES signal region

s(DE)=16.1

s(DE)=18.9

Cross-hatched background from sidebands

Missing energy effect

Sergio Grancagnolo


D e resolution ii
DE resolution (II)

Final values used in selection (MeV)

Better resolution for modes with a p0 (mass constraint)

Sergio Grancagnolo


Background rejection
Background Rejection

  • Reduction of the combinatorial background

  • Simulated signal events selected in signal region

  • Background from data events selected in DsJ mass sideband region

  • Curves represent

    fraction of events cut by

    m(D0g)> mcut(D0g)

  • Optimal cut set at the

    maximum separation

    between two samples

m(D*g) cut

Events rejected:

25% signal

75% backgrd

m(D*g)>2.4GeV/c2

Gev/c2

Sergio Grancagnolo


Optimization
Optimization

  • Maximized the significance ratio:

    S = simulated signal events in signal region

    B = background from data in m(DsJ) sidebands

Tried different cut levels for D and Dsusing PID, vertexing and helicity cut

f cos(qhel)

f mass

5000

40000

2500

20000

Tried different numbers of s cut for variables: DE, m(Ds), m(D)

-1

1

1.94

2.0

cos(qhel)

m(f)

Cleaner modes require less stringent cuts

Sergio Grancagnolo


Fit n i sig in d sj 2460 d s g
Fit nisig in DsJ(2460)+Ds+g

m(Dsg)

  • Finally, in selected candidates: m(Dsg)

  • Fit the background shape with a polynomial

  • Fit the signal peak with a Gaussianof fixed width

    • s=12 MeV

    • estimated in data

  • Events in the signal peak:

Entries/10 Mev/c2

GeV/c2

significance=11.7

nisig = 53.0±7.7

Sergio Grancagnolo


Efficiency and cross feed
Efficiency and Cross-feed

  • From gi=60k simulated signal events for each mode i

    • Efficiency:

      nisim= number of B0D*-DsJ(2460)+ events reconstructed in the corresponding simulated sample

    • Total cross-feed:

      nijsim= number of B0D*-DsJ(2460)+ events reconstructed in the simulated sample (mode j)

      fij= cross-feed from the mode j to the mode i

Typical efficiency range: 1-10%

depending on the presence of photons, soft tracks, stringent cuts, etc.

;

Sergio Grancagnolo


Narrow cross feed
Narrow Cross-feed

Efficiency

Reconstructed mode: B0D*0Ds1- [Ds-g]

m(DsJ)

Generated mode: B0D*0Ds1- [Ds-g]

nisim= 2778 gi=60000

ei=(4.63±0.08)%

Cross-feed

Generated mode: B0D*+Ds1- [Ds+g]

nijsim= 24 gj=60000

fij=(0.82±0.04)%

Narrow: sxfdssig

Sergio Grancagnolo

GeV/c2


Wide cross feed
Wide Cross-feed

Efficiency

Reconstructed mode: B0D0Ds1- [Ds-g]

m(DsJ)

Generated mode: B0D0Ds1- [Ds*-p0]

nisim= 1350 gi=60000

Cross-feed

ei=(2.25±0.07)%

Generated mode: B0D*+Ds0- [Ds-p0]

nisim= 144 gi=60000

fij=(0.24±0.02)%

Cross-feed

nisim= 162 gi=60000

Generated mode: B0D*0Ds0- [Ds-p0]

fij=(0.27±0.02)%

Wide: sxfd 2.5 ssig

Sergio Grancagnolo

GeV/c2


Branching ratios and cross feed
Branching Ratios and Cross-feed

An iterative procedure is needed:

  • Compute for each mode i without considering cross-feed

  • Estimate nixfdusing Brj and the cross-feed fij from all the modes

  • Subtract the number of cross-feed events

  • Compute the corrected branching ratio

  • Recompute the cross-feed iterating point 2-4 until convergence.

__

Sergio Grancagnolo



Fit results and significance
Fit Results And Significance

s=5.5

s=4.2

s=5.0

s=5.2

s=7.4

s=11.7

s=3.1

s=5.1

s=4.3

s=6.0

s=7.7

s=2.5

Sergio Grancagnolo


Main systematic errors
Main Systematic Errors

Depends on the tracks or photons number

  • Tracking efficiency 9%

  • g/p0 efficiency 5%

  • Background fitting model5%

    • Tried exponential instead of polynomial to fit background

  • DE width 5%

    • Changed the width of the DE signal region by ±3 MeV

  • DsJ width 3%

    • Varied by ±1 MeV the s of the Gaussian (12 MeV) that fit the signal

Modes with D*0 more affected

Sergio Grancagnolo


Branching ratios results
Branching Ratios Results

Phys.Rev.Lett.93:181801,2004

NEW!

NEW!

NEW!

NEW!

NEW!

NEW!

Sergio Grancagnolo

Measurements with significance>5


D sj 2460 angular analysis i
DsJ(2460)+ Angular Analysis (I)

_

  • Use B0DsJ+D-and B+DsJ+D0 with DsJ+Dsg

  • B DDsJ+is a transition 0- 0- JP so DsJis polarized

  • Compute the helicity angleqh of DsJ+Dsgand compare with the predictions for JP=1+ and JP=2+(0+forbidden)

Sergio Grancagnolo


D sj 2460 angular analysis ii
DsJ(2460)+ Angular Analysis (II)

DsJ events are fitted separately in 5cos(qh) bins

not used cut m(Dg)>2.3

Sergio Grancagnolo

Simulation is used to correct for detector acceptance


D sj 2460 angular analysis iii
DsJ(2460)+ Angular Analysis (III)

  • Expected distribution for JP=1+ is:

    1-cos2(qh)

  • Distribution compatible with this case

    • c2/d.o.f.=3.9/4

    • Supporting the Ds1+ hypothesis for this state

  • Comparison with JP=2+ hypothesis is also provided

    • c2/d.o.f.=34.5/4

Sergio Grancagnolo


Some comparisons with models
Some Comparisons With Models

  • Branching ratios smaller than the corresponding BD(*)Ds(*)

    • Factorization effects could be important and could not cancel in the ratios RD0,1

    • support a multiquark hypothesis

  • Observation of electromagnetic DsJ(2460)+ decay

    • supports a conventional cs picture

  • In agreement with prediction from chiral multiplets we measure:

Colangelo, De Fazio, Ferrandes: Mod.Phys.Lett. A19:2083,2004

Godfrey Phys.Lett. B568:254,2003

_

Bardeen, Eichten, Hill: Phys.Rev. D68:054024,2003

Sergio Grancagnolo


Conclusions
Conclusions

  • We combine 60 different final states to obtain 12 branching ratios BD(*)DsJ measurement with

    • The modes BD*DsJ with a D* or a D*0 are first observations

    • Extraction of JP=1+ quantum numbers of DsJ(2460)+

Sergio Grancagnolo



Babar run 5
BaBar run 5

Sergio Grancagnolo


Inner tracking and vertexing svt
Inner Tracking and Vertexing: SVT

Low pT track

Double side silicon microstrips

High pT track

  • Extrapolation of secondary vertex

  • Standalone tracking capability for low pt tracks

Sergio Grancagnolo


The detector of internal reflected cherenkov light
The Detector of Internal Reflected Cherenkov light

A charged particle traversing the DIRC produces Cherenkov light if bn>1

Sergio Grancagnolo


Particle identification de dx dirc
Particle IDentification:dE/dx, DIRC

For tracks with p<700MeV: dE/dx from DCH and SVT

For tracks with p>700MeV: Cerenkov angle from DIRC

Sergio Grancagnolo


Photons emc
Photons: EMC

  • Projective geometry

  • Discriminate between hadron and electromagnetic showers

  • Contribute to trigger

mp=134.5MeV

sp =6.4MeV

Sergio Grancagnolo

mgg (MeV)


Theoretical d sj interpretation references
Theoretical DsJ Interpretation References

  • Cahn, Jackson: Phys.Rev.D68, 037502 (2003)

  • Lucha, Schoberl: Mod.Phys.Lett. A18, 2837 (2003)

  • Bardeen, Eichten, Hill: Phys.Rev.D68,054024 (2003)

  • Beveren, Rupp: Phys.Rev.Lett.91, 012003 (2003)

  • Bali: Phys.Rev.D68, 071501 (2003)

  • Dai, Huang, Liu, Zhu: Phys.Rev.D68,114011 (2003)

  • Szczepaniak: Phys.Lett.B567, 23(2003)

  • Browder, Pakvasa, Petrov: Phys.Lett.B578, 365 (2004)

  • Barnes, Close, Lipkin: Phys.Rev.D68,054006(2003)

  • Maiani, Piccinini, Polosa, Riquer:Phys.Rev.D71.014028 (2005)

Sergio Grancagnolo


Low energy track efficiency from slow p
Low energytrack efficiencyfrom slow p

Sergio Grancagnolo


Reconstruction of soft pions
Reconstruction of Soft Pions

  • Fundamental to understand our capability of reconstructD*

  • Estimate tracking efficiencyfrom data itself

dm = m(D*+)-m(D0)=140.6 MeV

m(p)=139.6 MeV

We reconstruct: D*+D0 p+

Kp

JP

 Energy available for the p is very low

1- 0- 0-

Angular analysis

Expected symmetric angular distribution of the events in the D* frame

Helicity angle

D* direction of flight

Sergio Grancagnolo


Soft pion studies
Soft Pion studies

Separation of pion sample based on D* momentum

p(D*) bins

p(D*) GeV/c

Critical regions

For a given D* momentum:

Slower D*

 linear relationship

Sergio Grancagnolo


Background subtraction
Background subtraction

  • Use of two kinematic variables: m(D0), dm

  • Four categories of events:

  • Signal

  • Real-D0+bad-ps

  • Bad-D0+real-ps

  • Combinatoric background

  • Use of kaon and pion PID to distinguish between different contributions

m(D0)

dm

Background removal within each p(D*) bin, that cover the same soft pion kinematic range of the signal

Sergio Grancagnolo


Efficiency of soft pion
Efficiency of Soft Pion

cos(q*)

Efficiency estimate from asymmetries in the helicity angle distributions

Expected distribution (symmetric)

High p(D*)

Asymmetric distribution

Low p(D*)

Low cos(q*)

-1.0

0

1.0

Convolute the helicity distributions with an efficiency function parameterized as:

Sergio Grancagnolo


Soft pion efficiency results
Soft Pion Efficiency Results

  • Convoluting function parameters obtained minimizing a c2

  • Relative efficiency raise over 90% already at 100Mev/c

  • From the differences between data and simulation: a systematic uncertainty of 1.4% per track in the efficiency

Efficiency

Simulation

Data

p(p) GeV/c

Sergio Grancagnolo


Event selection i tracks
Event Selection (I): tracks

Tracks:

Kaon PID:

Photons and p0:

f:

Invariant mass:

Sergio Grancagnolo


Event selection ii d 0 d s
Event Selection (II): D0, Ds

Measure invariant mass m, and resolution s in data:

Apply the request:

- nss < m-m0 < nss

Sergio Grancagnolo


Another example
Another example

  • B0->D*-DsJ(2460)+, DsJ->Ds*pi0

    • We have D*->D0pi (soft p+)

    • Ds*->Dsgamma

    • D0,Ds as before

  • Pi0 veto on gamma

Sergio Grancagnolo


Background from b d d s
Background from BD(*)Ds(*)

  • IdenticalD(*),Ds(*) selection

  • B candidates selected in mES, DE signal region

m(Dsg)

Reject events with at least a candidate compatible with BD(*)Ds(*)

350

Events rejected

200

Events/10 MeV/c2

easily combine with lowenergyg or p0 to give a DsJ

0

Gev/c2

2.7

2.0

2.35

Background events that enter marginally in the DsJsignal region

Sergio Grancagnolo


Background events

Simulated ~220 fb-1 of generic events

No peaking background observed

Background Events

m(Dsp0)

  • Simulated ~60k events for each mode BD(*)Ds(*)

    • No peaking background observed

400

Entries/10 Mev/c2

200

2.4

2.2

Gev/c2

2.6

m(Dsp0)

100

Entries/10 Mev/c2

50

2.4

2.2

Gev/c2

2.6

Sergio Grancagnolo


Reconstruct b candidates
Reconstruct B candidates

60k signal events for each submode

Determine selection criteria using a simulation

DE

10000

Events/5 MeV/c2

5000

Resolution:

s=16 MeV

GeV

B candidates must enter in the signal box: mES, DE

If more than one B candidate is found, the one with the smaller difference DE-DE0 is retained

Sergio Grancagnolo


nisig = 34.8±7.9

s=5.5

nisig = 23.6±6.1

s=5.2

nisig = 32.7±10.8

s=3.1

nisig = 15.3±6.8

s=2.5

Sergio Grancagnolo


nisig = 17.4±5.1

s=4.2

nisig = 26.5±5.6

s=7.4

nisig = 28.0±5.8

s=5.1

nisig = 30.5±6.4

s=7.7

Sergio Grancagnolo


nisig = 24.8±6.5

s=5.0

nisig = 53.0±7.7

s=11.7

nisig = 32.0±8.2

s=4.3

nisig = 34.6±7.5

s=6.0

Sergio Grancagnolo


Other efficiency and cross feed
Other Efficiency and Cross-feed

  • In B+D0DsJ(2317)+ cross-feed is dominated by DKppD0Kpp0

10

m(DsJ)

m(DsJ)

DKpp reconstructed as D0 Kpp0

250

D0 Kpp0

Cross-feed

Efficiency

GeV/c2

GeV/c2

fij=(0.04±0.01)%

ei=(1.93±0.06)%

nisim= 1160 , gi=60000

Sergio Grancagnolo

nijsim= 24 , gj=60000


Isospin averaged branching ratios
Isospin averaged branching ratios

  • CombineD+ and D0 and D*+ and D*0 measurements

  • Average with statistical weightw=1/si2

  • To compare two measurementsx1 and x2 with variance s1 and s2 we use the variable z:

Sergio Grancagnolo


Ratios of branching ratios
Ratios of Branching Ratios

  • Compare BD(*)Ds and BD(*)DsJ measurements is possible through ratios:

  • Neglecting phase space we expect:

  • We know BD(*)Ds from PDG (1-5%)

  • Final results to be revised

Datta, O’donnell Phys.Lett. B568:254,2003

and similarly for RD*0 and RD*1

Sergio Grancagnolo


Comparison with belle
Comparison with Belle

Phys.Rev.Lett.93, 181801 (2004)

J.Phys.Conf.Ser.9:115-118,2005

Sergio Grancagnolo


Comparison with old belle results
Comparison with old Belle results

Phys.Rev.Lett.91:262002,2003

Experimental results compatible within errors

Sergio Grancagnolo


Conclusions1
Conclusions

“no compelling evidence that a non-standard scenario is required … neverthless unanswered questions remain …” (Review by P.Colangelo, F.De Fazio, R.Ferrandes, hep-ph/0407137)

Sergio Grancagnolo


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