H.Evans IU Seminar: 28-Apr-05 1 The b-Quark a Vertex of New Physics Hal EvansColumbia U.

H.Evans IU Seminar: 28-Apr-05 1

The b-Quarka Vertex of New Physics

The b-Quarka Vertex of New Physics

Hal Evans Columbia U.


What You’re In For…What You’re In For…

1. Overthrowing the Standard Model

2. The Revolutionary b-Quark and Its Role

3. Bs Mixing at DØ – The Next Campaign

4. What’s Coming in the Grand Flavor Plan


Standing on Solid GroundStanding on Solid Ground

LEP EW-WG: Winter 2005H

Higgs


If it ain’t Broke – Fix It !If it ain’t Broke – Fix It !

Why Look Beyond the SM ?

Has (at least) 19 arbitrary parameters

Does not include Gravity Why Mpl >> MEW?

Higgs Mass not stable to radiative corrections

~ Mplanck for no new phys Mh < 800 GeV

tuning to 10-16

No Motivation for EW Symmetry Breaking

222

20

2

4 hhh MM~M


Where Should We Look ?Where Should We Look ?

Start with the BIG Questions

1. Why is there Mass ? EW Symmetry Breaking

2. Antimatter ? Weak vs Mass States & CPV

3. What about Matter ? understanding QCD

Ask Them in the Right Way Look in New Places higher E, sparse meas More Precision new techniques

Two Particularly Promising Areas

a. The Neutrino Sector

b. EW Symmetry Breaking (related to 2. as well)


News Flash 2008 !News Flash 2008 !

But…

What Now ?

all the news that’s yet to print

Elusive Higgs Boson Discovered

By THE FREE ASSOCIATION PRESS

The scientific community was rocked yesterday when the ATLAS collaboration announced the discovery of the long-sought Higgs boson in a press conference at CERN. “This is an historic occasion.”, said Peter Higgs, the physicist after whom the particle is named…

ATLAS: H M(H) = 120 GeV

L = 100 fb-1


Lots of IdeasLots of IdeasThere are lots of Ideas… Dynamical Symmetry Breaking

Technicolor: running, walking, limping…

Supersymmetry (SUSY) GMSSM, SUGRA, R-Parity

Violating

Large Extra Dimensions testable string theory!

pp ff

pp VV

• monojets

• single VB

• f,VB-pairs

SuperpartnersStandard Model

½1

½0

½1

0½

0½

0½

SSparticleSParticle

RL q,q

RL ,

L

,Z,W 0

H,A,H,h 000

g

RL q~,q~

RL

~,~

L~

21~,~

04

03

02

01

~,~,~,~

g~

MSSM: M(h) < 135 GeV !!!

Most predict something very similar to the Higgs

Distinguish using input from many sources etc., etc., etc….


The Symmetry–Flavor ConnectionThe Symmetry–Flavor Connection

The SM has a Lovely Plan for EW Sym Break & Mass

SM Symmetries & Yukawa Couplings Quark Mixing

Mixing (CKM) Matrix: Vij

EW Sym Breaking Observed Flavor Structure

.]c.hUQyDQyELy[L jR

iL

uij

jR

iL

dij

jR

iL

familyj,i

eijY

diagonal-non s,comp' imag.

diagonal real, )convention (by

dij

uij

eij

y

y,y

i j,i

jRij

iL

dj

iR

iL

uiY .]c.hDVQy[]c.hU~Qy[L

b u

W-

2ubgVFamily Changing

Decays Mixing

s

t

t

s

b

b

WW0sB 0

sB


Mixed Up QuarksMixed Up Quarks

Quark Weak Mass Eigenstates CKM Mixing Matrix 3 angles 1 complex phase CP-violation Obs. CPV requires m(qi) ≠ m(qj)

Wolfenstein Parameterization

Strength of CPV J = A2 6 ~ (710-5)

1121

1

21

1

23

22

32

A)i(A

A

)i(A

b

s

d

VVV

VVV

VVV

'b

's

'd

tbtstd

cbcscd

ubusud

Wea

k

Mas

s

CKMFitter Group: hep-ph/0406184

very different hierarchy than Lepton Mixing Matrix

04600420

08800700

0025000230

02900200

3580

1890

22650

8010

.

.

.

.

.

.

.

.

.

.

.

.A


Why is Flavor Promising (1)Why is Flavor Promising (1)

The SM has a very Specific Flavor Sector:Only one Higgs Doublet

1. FCNC’s suppressed

2. Universal Charged Current

3. VCKM is Unitary

4. 1 Parameter describes strength of all CP Violation


Getting to Know the BGetting to Know the B

Weakly Decaying B Hadrons

Large Mass Many Decays >100 observed for Bd

small QCD corr’s to pred’s

Long Lifetime (B) ~ 4 (D) ~ 5 () flight lengths O(1mm) at

colliders exp’s

Neutral B-Mesons Mix 1987: obs by ARGUS & UA1 predict heavy top 8 years before direct obs.

B-Hadrons exhibit large CPV structure of CKM matrix

Hadron Mass [MeV] Life [ps]

5279 1.67

5279 1.54

5370 1.46

6400 0.5

5624 1.23

u)b( B

d)b( B0d

s)b( B0s

c)b( Bc

(bdu) 0b s

t

t

s

b

b

WW0sB 0

sB

Meson m [ps-1] /

Bd 0.5 < 0.01

Bs > 15 < 0.3

K0 0.005 ~1


The Beautiful TriangleThe Beautiful Triangle

Unitarity of VCKM 6 triangles:

one has all sides ~ equal

Angles CPV in B0 ,, CPV in B0 J/

K0,,’ CPV in B0 ,,’ K0

CPV in B± D0 K±

CPV in B0 D(*)+ -

Sides Ru B.R.(B Xc,u lv)

Rt Bd Mixing

Other , CPV in K0 system

K+ + v v K0 0 v v N.P. Bd,s +- , +- Xd,s

0 *tdtb

*cdcb

*udub VVVVVV

(0,1)

(0,0)

(,)

*

ubud

*tbtd

VVVV

arg

t*cbcd

*tbtd R

VV

VV

*

tbtd

*cbcd

VVVV

arg

*

cbcd

*ubud

VVVV

arg

*cbcd

*ubud

u VV

VVR

Unitarity Triangle


Putting Things TogetherPutting Things Together

Param Mode Meas

sin 2 0.726 ± 0.037

0.43 ± 0.07

(113 ± 27)o

Acp(BD(*)K) (69 ± 20)o

|Vcb| x 103 BD(*)/Xc lv 41.4 ± 2.1

|Vub| x 103 BXu lv 4.70 ± 0.44

|K| x 103 KL, KS 2.282 ± 0.017

md (ps-1) Bd mixing 0.502 ± 0.006

ms (ps-1) Bs mixing > 14.4

s)cc(b cpA

s)qq(b cpA

d)uu(b cpA

CKMFitter – ICHEP 04HFAG summer 2004

SM Fit Probability ~ 70%

CKM Phase probably the dominant source of CPV in FC processes

(damn !)CKMFittersummer 01


Why is Flavor Promising (2)Why is Flavor Promising (2)

CKM Phase as only Quark-Sector CPV is ODD most Models beyond SM lots of new CPV phases

43 in generic SUSY models ! FCNCs are also generally large Beyond the SM

Flavor Physics is Already a Major Constraint on Physics Beyond SM Note that the 3rd Family is the least well constrained

What’s Left Then? (some examples) Minimal Flavor Violation GMSB, univ.E.D.

only source of FV is in Yukawa couplings New Sources of CPV R.-S. w/ bulk q’s

FV parts have to be suppressed by e.g. heavy mass scales

Both can Modified Coupling Strengths enhanced rare decays

General Scheme different models predict different relationships b/w observables

c.f. sin 2 in B J/ Ks vs. B Ks


Natural Habitats of the b-QuarkNatural Habitats of the b-Quark

Q

Q

p

p

Incoming Particles

HardInteract

OutgoingParticles

p

e

e+

e-

ij

ij

ij

Machine √s (TeV)

(bb) (b)

Rate (Hz)

<L>(mm)

B’s

LHC(Atlas,CMS,LHCb)

14 500 25K 1.5 all

Tevatron(DØ,CDF)

1.96 100 600 0.5 all

HERA(H1,Zeus)

0.32 ~0.010 >0.1 all

Z-Fact(LEP, SLC)

0.09(to 0.20)

0.007 0.07 3 all

B-Fact(BaBar,Belle,CLEO)

0.01 0.001 10 0.3 Bd, B+

p –

p(b

ar)

e –

pe+

– e

-


Fermilab & Flavor PhysicsFermilab & Flavor PhysicsHistory

Commissioned 1967 Tevatron (p-pbar) 1983 Main Injector 1999 Run II Start 2001

Some Highlights b-quark discovery: 1977

Lederman, et al t-quark discovery: 1994

CDF & DØ

discovery: 2000 DONUT


The Tevatron ColliderThe Tevatron ColliderWorld’s Highest E Accelerator

proton – antiproton collisions ~4 miles circumference >1000 supercond. magnets

Main Injector(new)

Tevatron

DØCDF

Chicago

p source

Booster

Ib

92-96

IIa (now)

IIb

(goal)

E-CM [GeV] 1800 1960 1960

Collisions [ns] 3500 396 396

Peak Lumi. (x1031)

[cm-2s-1] 0.16 10 28

Tot Lumi fb-1 0.125 0.9 4-9


DØ CollaborationDØ Collaboration

650 people84 institutions19 countries


DØ Detector (the cartoon)DØ Detector (the cartoon)Central Scintillator

Forward Mini-drift chamb’s

Forward Scint

Shielding

Tracking: Solenoid(2T), Silicon,FiberTracker,Preshowers

New Electronics,Trigger,DAQ

Calorimeter

Central PDTs


The Real McCoy !The Real McCoy !

~1M Channels

2.5M Event/s

250 KB/Event


DØ à la carteDØ à la carte

DØ is a General Purpose DetectorDesigned to Study a Huge Range of Physics Topics

QCD Understand the strong force where it is predictive Background for all other physics

B Physics QCD at perturb/non-perturb interface Probe quark mixing Indirect evidence for new physics

W/Z QCD Tests Precision measurement of EW parameters

Top Precision measurement of EW parameters Most massive particle new physics

Higgs The heart of EW symmetry breaking

Searches Directly look for new particles/effects predicted by specific beyond the SM models


Data Collected & AnticipatedData Collected & Anticipated

Run II Data so Far Apr 2001 start of Run

II Apr 2002 DØ fully

commiss. ~700 pb-1 collected to now 450 pb-1 analyzed

Run II Projections (June 04) inst. lumi. 2.8x1032 cm-2s-1

total data 4 – 9 fb-1

DØ upgrade: October 2005

current peak L

install upgrades


Flip-Flopping B’sFlip-Flopping B’s

Weak Mass Eigenstates Neutral B’s can mix

Time Evolution

matrices 2x2 Hermitian

2

,M

)t(B

)t(BiM

)t(B

)t(B

dtd

i

]1[

]1[

00

00

)tmcos(e)t)(BB(P

)tmcos(e)t)(BB(P

qt

qq

qt

qq

q

q

sd,

t

t

s,d

b

b

WW0

sd,B 0sd,B

*tbV

tbVstd,V

*std,V

t (lifetimes)

Pro

bab

ility

2222

2

6*

tbtqqBqBqBtWF

q VVBfmxSmG

m


Mixing Now !Mixing Now !

md = 0.502 ± 0.006 ps-1

30 separate measurements !

ms > 14.4 ps-1 (95% CL)

Heavy Flavour Averaging GroupWinter 2005 update


Some Hints ?Some Hints ?

Results presented as“Probability” that data is consistent with oscillations at various values of ms

ObservationStatistically significant Amp(ms) = 1

95% C.L. LimitAmp + 1.645 = 1

SM Preferred Region

16.2 – 24.5 ps-1 (“1 ”)

SM Preferred Region

16.2 – 24.5 ps-1 (“1 ”)HFAG: winter 2005

CKMFitter: ICHEP 2004


The Importance of B’ing StrangeThe Importance of B’ing Strange

Bd Mixing |Vtd| (side of triang.)

So Why should we bother with Bs ?

s

d

Bd

Bs

BdBd

BsBs

ts

td

mm

mm

BF

BF

V

V

Ratio reduces error: 14% 5%


Anatomy of a Bs Mixing AnalysisAnatomy of a Bs Mixing Analysis

1. Identify Bs Candidates produce them get them to tape reconstruct them

2. Determine Proper Time decay length ct = L /

3. Tag Mixed or Unmixed flavor at production flavor at decay

4. Fit for ms

or ampl at ms

Significance of Observation

S = no. of Bs signal cand’s = frac. of cand’s w/ tag D = 2xProb(tag) – 1 S/B = signal/ bgrd t = ave. proper time res.

22

2

2Signif /)m( tse

BS

SDS

-B

K

0D0sB

-sD

K

K


Finding the Elusive BsFinding the Elusive Bs

1. Produce a Bs

fs ~ 0.1 vs. fd = fu ~ 0.4

2. Trigger on the Event Collision Rate 2.5 MHz Rate to Tape 50 Hz Trigger on 1 or 2 ’s

3. Reconstruct Bs

Ds(*) l v BR ~ 10%

more stat’s

poorer t (can trigger on lepton)

Ds(*) n BR ~ 0.5%

less stat’s

better t Ds , K*0K

KK, K*K

-B

K

0D0sB

-sD

K

K

Experimental Challenges determining backgrounds Low Pt trigger lepton Low Pt tracks

-B

K

0D0sB

-sD

K

K


We Reconstruct B’s !We Reconstruct B’s !

Mode evts / 100pb-1

J/ + - 1.14 M

B+ J/ K+ 1700

Bd J/ K*0 740

Bd J/ K0S 40

Bs J/ 100

b J/ 25

Bc J/ X 65

X(3872) J/ + - 230

B D** v 210

B** B 150

Bs Ds1 X 5

B+ D0 + X 46.2 K

Bd D*- + X 10 K

Bs Ds() X 2900

Bs Ds(K*K) X 2500

210 pb-1

N = 135±18M = 6.1±0.2±0.4 GeV

Bc J/ X

Bs J/

450 pb-1

N = 483 ± 32


Mixing SamplesMixing SamplesP

reli

min

ary

Bd M

ixin

g

Pre

lim

inar

y

Bs

Mix

ing

250 pb-1

B D0 X~83% B+

200 pb-1

B D* X~85% Bd

200 pb-1

B K*K X

Bs Ds X4930 ± 380200 pb-1

B X

Bs Ds X13340 ± 280

450 pb-1


How Long Does It Live ?How Long Does It Live ?

1. Estimate Decay Length (Lxy) Beam Spot

size ~35 m in x-y

Bs Decay Point vertexing

Decay Length Error (L)

2. Estimate B Momentum ct = L / Bs Ds

(*)

very precise Bs Ds

(*) l v

missing v must use MC to est. corr.

-B

K

0D0sB

-sDK

K

3. Proper Time & Error

Experimental Challenge understand resolution

KPM

Lct meast

Bxy

22

0

2

Kt

LK

BB

L

B

t


Study Resolution w/ LifetimesStudy Resolution w/ Lifetimes

(t))N(B

)N(B0

Bc J/ X

210 pb-1

440 pb-1

s J/

250 pb-1

Bs Ds X

400 pb-1


Lifetime ResultsLifetime Results

Lifetime Measurements at DØ compared with World Ave’s

(from HFAG)

Bs Lifetime Difference

3

SM

104

~ms

s

Bs J/ 450 pb-1


To Mix or Not To MixTo Mix or Not To Mix

1. Tag Flavor at Production Opposite Side

Soft Lepton (muon) Tag -charge b-charge

Jet Charge Tag–

Same Side Charge of leading non-Bs

hadron– B** B h or fragm

2. Tag Flavor at Decay -charge b-charge

Experimental Challenge Measure mis-tag rate in Data Control Samples: B± decays

B+ D0 +, B+ J/ K+

-B

K

0D0sB

-sD

K

K

h

i,t

ii,t

P

qP Q Jet

Method (%) D (%) D2 (%)

Soft Muon 5 45 1.0 ± 0.2

Jet-Q / Same Side 68 15 1.5 ± 0.3

BaBar/Belle ~20


Contributions to Mixing UncertaintyContributions to Mixing Uncertainty

50K Simulated Bs Ds v Events: ms = 15 ps-1

cs

reduces ampl of osc big effect at large t

big effect at small t


Testing the Waters with Bd MixingTesting the Waters with Bd Mixing

m & D from Unmix – Mix Asymmetry

Agrees with Previous Measurements

DØ

Pre

lim

inar

y: 2

00 p

b-1

ctvis (m)

Un

mix

-Mix

Asy

m(t

)

“B+” D0 + X(JetQ+SST)

“B0” D*- + X(JetQ+SST)

“B0” D*- + X(SLT)

cd mxcosD~

xNxN

xNxNxA mixunm

mixunm


First Try at msFirst Try at ms

Bs Ds() X460 pb-1

No Oscillations Evident

Set Limits

Bd

B+

Dilution44.8 ± 4.2 %

Dilution46.8 ± 3.0 %

Fermilab Result of the Week: March 10, 2005


Still Only a Limit…Still Only a Limit…

ms > 5.1 ps-1 (95% CL)ms > 5.1 ps-1 (95% CL)

CDF prelim (Moriond): ms > 7.9 ps-1

Expected Limit ComparisonExpected Limit Comparison

comb. sens18.1 ps-1


…but Nostradamus Predicts…but Nostradamus Predicts

Mode Yield / pb-1 D2 (%) S/S+B t (fs)

curr. () 29 1.2 0.4 150

Ds() X 30 2.5 0.4 125

Ds() e X 30 1.25 0.4 125

Ds(K*K) X 25 2.5 0.2 125

Ds(*) 0.5 25 0.5 110

Significance for1 fb-1

Signif2

1~ m)(

Extra Improvement from:

• more powerful statistical techniques


The Road Ahead for DØThe Road Ahead for DØ

1st obs good accuracy

Other B-Physics Meas’s benefit greatly from increased statistics

Big Challenges: Triggering Level-1 Bandwidth

Limitations Data to Tape

& Reconstruction

Run II Projections (June 04) inst. lumi. 2.8x1032 cm-2s-1

total data 4 – 9 fb-1

DØ upgrade: summer 05

current peak L

install upgrades

Signif2

1~ m)(


The Current DØ Trigger SystemThe Current DØ Trigger System

Problem as Rates IncreaseReadout not Deadtimeless

L1 Accept Deadtime while data is digitized & stored to buffers

2.5 kHz L1A 5% Dead

CAL

c/f PS

CFT

SMT

MU

FPD

L1Cal

L1PS

L1CTT

L1Mu

L1FPD

L2Cal

L2PS

L2CTT

L2STT

L2Mu

Global L2Framework

Detector

Lumi

Level 1 Level 2

2.5 Mhz 3 khz 1 khz

Level 3


The Scope of the ProblemThe Scope of the Problem

Term Proc eff Run IIa

2-Jet + MEt vvbb 85% 2.1 kHz

1-EM W ev 86% 440 Hz

Hi Pt Trk (iso) Pt>10 98% 17 kHz

1- + Track W v ~90% 6 kHz

Trigger Problems Solutions

Jet(L1Cal)

1) Trig on =0.20.2 TTs slow turn-on curve, high rates

Clustering

EM(L1Cal + Cal-track)

1) ~Linear rate increase w/ lumi affected by noise

Clustering & Isolation Cal-Track Match

Track(L1CTT + Cal-Track)

1) Rates sensitive to occupancy 100 increase now21032

Narrower Track Roads Improve Cal-Track Match

Muon(L1Muon + L1CTT)

1) Mainly from tracking Requires Track Trig

2.5 kHzLimit

2.5 kHzLimit


The New SystemThe New System

CAL

c/f PS

CFT

SMT

MU

FPD

L1Cal

L1PS

L1CTT

L1Mu

L1FPD

L2Cal

L2PS

L2CTT

L2STT

L2Mu

Global L2Framework

Detector

Lumi

Level 1 Level 2

2.5 Mhz 3 khz 1 khz

Level 3

CalTrk

Installation

Oct. – Dec. 2005

Installation

Oct. – Dec. 2005


An Example: L1CalAn Example: L1Cal

Novel Implementation Challenge LM Finding Data Distribution Nightmare ! Solution All Data Transmission & Arithmetic done Bit Serially

New Algorithms: search for Local Maxima & Cluster

LM Finding Jet Algorithm Tau Algorithm EM Algorithm

Serial Adder(like 50’s-era computers)


With Trigger ImprovementsWith Trigger Improvements

Term Proc eff Run IIa Run IIb

2-Jet + Met vvbb 85% 2.1 kHz 0.8 kHz

1-EM W ev 86% 440 Hz 260 Hz

Hi Pt Trk (iso) Pt>10 98% 17 kHz 1 kHz

1- + Track W v ~90% 6 kHz 1.1 kHz

Triggering and B-Physics

without Trigger Upgrade all DØ Physics is Compromised

with Trigger Upgrade high PT abilities retained or enhanced

new Flexibility creates room for low PT (B-Physics) Triggers


DØ,CDF BaBar,Belle LHCb Atlas,CMS

Beams e+e- pp pp

ECM [TeV] 1.96 0.0106 14 14

Timeframe now 2009 now 2008 2007 2007

Inst Lumi(1032 cm-2s-1)

1.0 2.8 100 2.0 100

Data Set [fb-1] 0.5 9 150 500 1012 bb/yr 100/yr

Further Down the PathFurther Down the Path

pp


The Next StepsThe Next Steps

Quantity Mode Curr. W.A. Next Step Improvement

|Vcb| BXclv (41.4 ± 2.1)10-3 theory

|Vub| BXulv (4.70 ± 0.44)10-3 theory

ms BsDslvX,Ds > 14.4 ps-1 DØ,CDF ~20-25 (5 w/ 2 fb-1)

LHCb ~50 (1 year)

sin 2 0.726 ± 0.037 BaBar,Belle ± 0.03 (0.5 ab-1)

CDF,DØ ? ± 0.03 (2 fb-1)

0.43 ± 0.07 BaBar,Belle ± 0.03 (1.5 ab-1)

BD0CPK,K (69 ± 20)o BaBar,Belle ±14o (1.0 ab-1)

B,, (113 ± 27)o LHCb ±4o (1000 tag )

Rare BR(Bs+-) < 3.7 10-7 Atlas,CMS (3.5±0.8)10-9 (100fb-1)

Rare K’s BR(K+vv) NA48/3 ~50 evts (2 years)

BR(K0vv) < 5.910-7 KOPIO/E391 O(100) evts – 2009

sccb

sqqb

103010.89- 101.47 .


ConclusionsConclusions

B-Hadrons provide a Sensitive Probe of EW Symmetry Breaking & Physics Beyond the SM allow classes of models to be favored/ruled out complementary to direct searches for new particles

The DØ Experiment is Poised to make Major Contributions in the next few years CKM: Bs Mixing, s, sin 2, sin 2s… QCD: lifetimes, spectroscopy, production… Rare: Bs+-, B K*+-

Future Experiments will keep b’s at the Vertex of New Physics for many years to come !


Backup SlidesBackup Slides


Bs Event SelectionsBs Event Selections

Selection Ds+ (K+K-) + Ds

+ K*0(K+-) K+ (differences)

Muons penetrate toroid matched track: SMT+CFT Pt > 1.5, P > 3 GeV || < 2

same

Ds Candidate 3 tracks in same jet as w/ hits in SMT+CFT & correct Q || < 2 Pt(trk) > 0.7 GeV -mass (1.006<MKK<1.030 GeV)

3-track vertex: 2 < 16 (T/)2+(L/)2 > 2(), 4(one K)

dTD/ > 4 & cos(T

D) > 0.9

Pt(trk) > 1.0 GeV K*-mass (0.84 < MK < 0.96)

2(Ds) < 20 & 2(K*) < 20

(T/)2+(L/)2 > 2(), 5(one tk)

dTD/ > 4 & cos(T

D) > 0.95

dTD · P(D) > 0

cos(helicity-angle) > 0.60

Bs Candidate - Ds vertex: 2 < 9

1.5 < M(Ds) < 5.5 GeV

dTB < dT

D + 3

P(Ds) > 8 & PTrel > 1 GeV

- Ds vertex: 2 < 20

2.2 < M(Ds) < 5.5 GeV

In Ds M Peak 29 ± 0.6 events per pb-1 25 ± 2 events per pb-1


Selection Bias vs VPDLSelection Bias vs VPDL

Bs + v Ds X MC


Proper Time ResolutionProper Time Resolution

Primary Vertex evt-by-evt determination

using ave PV as seed

VPDL Resolution parameterized from MC for

each sample w/ 3 Gaussians IP errors (main contrib)

tuned using data tracks from PV depending on SMT hits

True Proper Time convolute over K-factor

distributions in Asym. prediction

K = PT(Ds) / PT(Bs)


Initial State Tagging ProcedureInitial State Tagging Procedure

Use “other” B in the evt to tag prod flavor of Bs

allow use of Bd mixing sample to measure eff and dilution “tagging” B essentially independent of “signal” B

cannot do this for “same side” tagging

Define a Tagging Variable using an optimal combination of variables sensitive to initial flavor

Variables Used All Events Events w/ Secondary Vertex

svari ii

ii

xb

xby

y

yd

1

1

trksi i

iT

iT

iJet p/pqQ

qprelT

trksi i

.iT

.iT

iSV p/pqQ

6060


Binned AsymmetryBinned Asymmetry

Nunm/mix in each VPDL bin fit Ds mass distrib for

unm/mix events in that bin single Gauss for Ds &

D+, exp for bgrd param’s fixed from untagged

sample mass fit

Sample Composition (Peak)

Ds Tagged Events-0.01 < VPDL < 0.06 cm

Process BR x Eff (%)

Bs v Ds- 20.6

Bs v Ds-* 57.2

Bs v Ds0*- 1.4

Bs v Ds1’- 2.9

Bs Ds+Ds

-X, Ds v X 11.3

B+ D Ds X, D v X 3.2

B0 D Ds X, D v X 3.4

cc Ds X 3.5


Reconstructed B’sReconstructed B’s

Bd J/ Ks0

B± J/ K±

B D* X

’ J/ + -

X(3872) J/ + -


The J/The J/


ResonancesResonances

= 7 MeV

= 3 MeV


Theoretically Clean FCNC B0 decays forbidden

at tree level in SM

Can be large beyond SM 2HDM tan4 MSSM tan4

Plays to DØ’s Strengths Muon Triggers to large Low Backgrounds also Bs + -

Rare Decays and FCNCsRare Decays and FCNCs

Mode BR(Bd) BR(Bs)

+- 1x10-10 4x10-9

+-K* () 1.5x10-6 1x10-6

+-Xs 6x10-6

K* 4.4x10-5

BR(Bs + -) < 3.710-7 (95% CL)BR(Bs + -) < 3.710-7 (95% CL)

+ - Mass [GeV]

300 pb-1


Measuring Measuring

d

b

0dB

W

*cbV

csVs

c

c

d0K

J/

b

d

W

t

t b

0dB 0

dB s

c

c

d0K

J/

tbV *tdV

tdV *tbV *

cbV

csV

s

c

cW

b

d

0dB

s

d0K

cc J/

cbV

*csV 0K

*cdV

*cdV

csV

*csV

s)cc(b KJ/B 0s

b

dW

tt b

0dB 0

dB 0K

tbV *tdV

tdV *tbV

*cbV

csV

c

d

q

q

s

',

b

d

0dB

c cc

csV *cdV

s0K

s

q

q',

0Kd

cdV *csV

cbV

*csV

b

0dB 0K*

cbV csV

c

d

q

q

s

',

d

s)qq(b KB 0s ',

fCP

fCPfCP A

A

p

q

B-Mixing Decay

i

cd*

cs

*cdcs

cs*

cb

*cscb

td*

tb

*tdtb e

VV

VV

VV

VV

VV

VV)K( 20

i

cd*

cs

*cdcs

cs*

cb

*cscb

td*

tb

*tdtb e

VV

VV

VV

VV

VV

VV)K( 20

H.Evans IU Seminar: 28-Apr-05 1 The b-Quark a Vertex of New Physics Hal EvansColumbia U.

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Transcript of H.Evans IU Seminar: 28-Apr-05 1 The b-Quark a Vertex of New Physics Hal EvansColumbia U.