# Presentation: 042057

## Mike Strauss
The University of Oklahoma
for the CDF and DØ Collaborations

- The University of Oklahoma
- for the CDF and DØ Collaborations

**Measurements of the Masses, Mixing, and Lifetimes, of B Hadrons at the Tevatron**

- 5th Rencontres du Vietnam
- Hanoi, Vietnam
- August 5-11, 2004

## B Physics at the Tevatron
B Resonances
B0 oscillations
B Lifetimes 
Exclusive Decays
Lifetime Ratios and Differences

***B***** Resonances**
***B*****0**** oscillations**
***B***** Lifetimes **
**Exclusive Decays**
**Lifetime Ratios and Differences**

**Outline**

## Tevatron Luminosity

- ~0.3 fb–1 delivered this year
- Detectors collect data at typically 85% efficiency
- These analyses use 150–350 pb–1
- About 150 pb–1 of data has been recorded but not yet analyzed

## B Physics at the Tevatron

- Large production cross sections
- All *B* Hadrons produced (Best *B*s and b)
- Larger inelastic cross section (S/B  10-3)
- Specialized Triggers:
- Single lepton triggers
- Dilepton triggers
- 	(e.g. J/ +)
- L1 Track triggers
- L2 displaced track trigger for CDF

- (ppbb)  150 b at 2 TeV
- (e+ebb)  7 nb at Z0
- (e+ebb)  1 nb at (4S)

## Detectors

- High rate trigger/DAQ, Calorimeter, Muon system

- Excellent muon ID;   || < 2
- Tracking acceptance || < 2-3
- L3 trigger on impact parameter

**Detectors**

- L2 trigger on displaced vertexes
- Low *p* particle ID (TOF and dE/dx)
- Excellent mass resolution

**CDF**

**DØ**

## X(3872)

** ****730 ******** 90 candidates**
** ****~****12 ******** effect**

*M**X* = 3871.3  0.7 (stat)
- 	         0.4 (sys) MeV/c2

- Belle: *M**X* = 3872.0  0.6 (stat)  0.5 (sys)

***X*****(3872)**

**CDF and D****Ø**** ****have confirmed Belle’s discovery of the *****X*****(3872)**

- *M* = 774.9  3.1(stat)
- 	        3.0 (sys) MeV/c2
- *M* +*M*(*J*/**) = 3871.8 4.3 MeV/c2

## X(3872) – (2S) comparison

**Is the *****X***** charmonium, or maybe an exotic meson molecule?**

- CDF Long-lifetime fraction:
**(2S): 28.3±1.0(stat) ±0.7(syst)
*X*(3872): 16.1±4.9(stat) ±2.0(syst)

- DØ multi-parameter comparison

## First Observation of BS  

- BR(*B*s**) = 1.4 ± 0.6(stat) ± 0.2(syst) ± 0.5(BR)×10-5

**Notes:**
Sensitive to QCD Penguin diagrams

## Search for B0(s,d)+–

**Search for *****B*****0****(s,d)**************+**********–**

- SM BR(*B*s0**+**-)(3.40.5)×10-9;  BR(*B**d*0**+**-)(1.50.9)×10-10

- BR(*B*s0**+***–*): < 7.5×10-7
- at 95% CL (CDF)

- BR(*B*d0**+***–*): < 1.9×10-7 at 95% CL

- Expected BG: 1.05 ± 0.30

- BR(*B*s0**+***–*): < 4.6×10-7
- at 95% CL (DØ)

- Expected BG: 3.7 ± 1.1 events

**Notes:**
Can be enhanced by various SUSY models, including Rp violating SUSY, minimal supergravity with  large tan(beta), and SO(10) models.
Previous B_s = 2.0×10-6 at 90% CL

## Observation of B**

*B* Spectroscopy:
*B* (*J**p* = 0–)
*B** (*J**p* = 1–) – decays to *B*γ (100%)
- Δ*M* = *M*(*B**) – *M*(*B*) = 46 MeV/c2
- The *B*** consists of four separate states
- 2 narrow states *B*1 (1+) and *B*2* (2+), decay via D-wave;
- 2 wide states *B*0* (0+) and B1*' *(1+), decay via S-wave;
- None of these individual states are well established
- Decay channels used:
*B**d****B*±**+; *B***+*B**d***+; *B****B**** *B*** (γ)
*B* *J*/** *K*±; *B**d*  *J*/** *K**0; *B**d*  *J*/** *K*0s

- –

**Notes:**
Combine B+** and B0** because mass difference is small, expected to be about 3 MeV

## Distinct Narrow B** States

*M*(*B*1) = 5724 ± 4 ± 7 MeV /c2
*M*(*B*2*) – *M*(*B*1) = 23.6 ± 7.7 ± 3.9 MeV/c2

- 350 pb–1

- The first direct measurement of masses and splitting between *B*2* and *B*1
*M*(*B**) = *M*(*B*) +
- 		       46 MeV ()

*B*1*B***()

*B*2**B*** ()

*B*2**B***

- Sum of 3 decay modes

**Notes:**
Chi2 of fifteen different for 1 peak, vs three peaks.

## Bd Mixing

- In SM *B**d* mixing is explained by box diagrams
- Constrains Vtd  CKM matrix element
- Mixing frequency *m**d* has been measured with high precision at *e*+*e*– *B* factories (0.502  0.007 ps-1)
- *m**d* measurement at Hadron Colliders
- Confirms initial state flavor tagging for later use in *B**s* and *m**s* measurements

**Notes:**
B Bbar are independent decays and fragmentaion.  No coherence

## B Oscillation Variables

- _Opposite side_

- _Same side_

- b–1/3 Q<0

*B*s*K*+
- (CDF)

- b  *K*–
- (CDF)

## B0 Mixing with SS Tag

***B*****0**** Mixing with SS Tag**

- A = (NRS – NWS )/(NRS + NWS )

- NRS:N(*B*0**+)
- NWS:N(*B*0**–)

**Notes:**
One of the best measurements at a hadron collider. SC is sample composition

## B0 Mixing with SS Tag

***B*****0**** Mixing with SS Tag**

*B****D***X*, *D***D*0**

- Preliminary

- Visible Proper Decay Length:
*x**M* = *L**xy** M**B** c* /*p**T****D*

- Tagging purity: 55.8 ± 0.7 ± 0.8 %

**Notes:**
One of the best measurements at a hadron collider

## B0 Mixing with OS  Tag

**Decay Mode:**
*B****D***X*, *D***D*0**
**Tagging:**
- muon *p**T* > 2.5 GeV/c
- cos *****B* < 0.5
- Tagging efficiency:     	4.8 ± 0.2 %
- Tagging purity:         	73.0 ± 2.1 %
**Fit procedure**
-  Binned 2 fit

***B*****0**** Mixing with OS ********** Tag**

- Preliminary

- Combined result using three tagging methods will be released soon

**Notes:**
One of the best measurements at a hadron collider

## Naive quark spectator model: a 1  3 decay process common to all B hadrons. 
(NLO) QCD  Heavy Quark Expansion predicts deviations in rough agreement with data
Experimental and theoretical uncertainties are comparable 
Lifetime differences probe the HQE to 3rd order in  QCD / mb 
Goal: measure the ratios accurately	       

- (NLO) QCD  **Heavy Quark Expansion** predicts deviations in rough agreement with data
- Experimental and theoretical uncertainties are comparable*** ***
- Lifetime differences probe the HQE to **3****rd** order in  ******QCD ****/ m****b**
**Goal: measure the ratios accurately*****	*****      **** **

**B Hadron Lifetimes**

## B Hadron Lifetime Ratios

## b Lifetime

- New Measurement from DØ
***b**J*/** **0

- DØ Preliminary

- CDF Preliminary from 2003:

*****b*) = 1.25 ±0.26 ±0.10 ps

- DØ

- DØ

## Bs Lifetime using BsJ/ 

- Improvements since 2003:
- Selection minimizes
***stat***** ******** *****syst***
- 12 parameter maximum likelihood fit
- 240 pb-1

- CDF

- DØ

- Preliminary

- 250 pb-1

- Preliminary

- DØ analysis is similar to this CDF “improved” analysis

**Notes:**
Assuming one exponential for signal.  Two exponentials later.

## Bs Lifetime using BsJ/ 

***B**s*) = 1.369±0.100         ps

- -0.010

- +0.008

- CDF

- DØ

- Uses one exponential decay in the fit

- Preliminary

- 250 pb-1

- Preliminary

**Notes:**
Assuming one exponential for signal.  Two exponentials later.

##  Bd Lifetimes Using Bd  J/ Ks*0

** *****B******d***** Lifetimes Using *****B******d ********* *****J*****/********** *****K******s**********0**

***B**d*0) = 1.473          ±0.023 ps

- 250 pb-1

- -0.050

- +0.052

- Preliminary

- CDF

- DØ

***B*0) = 1.539±0.051±0.008 ps

***B**s*)/***B*0) = 0.890±0.072

##  B+ Lifetime Using B  J/ K+

** *****B******+***** Lifetime Using *****B***** ******** *****J*****/********** *****K*****+**

***B*+) = 1.662±0.033±0.008 ps

***B*+)/***B*0) = 1.080±0.042

- Most systematic uncertainties cancel in the ratio

## Lifetime Ratio (B+)/(B0)

- Novel Analysis Technique using *B*  ***D*c(*)*X*

- Directly measure ratio instead of individual lifetimes
- Split *D*0 *K***sample:
*D**+ (with slow **    mainly from *B*0
*D*0    mainly from *B*+

- B0

- PV

- ν

- D0

- μ+

- K+

- π-

- μD0

- π-

- D*-

- 86% B0

- 12% B+

- 2% BS

- 16% B0

- 2% BS

- 82% B+

*D**+

*D*0

## Lifetime Ratio (B+)/(B0)

- Measure *N*(***D**+)/*N*(***D*0)** **in bins of VPDL
- In both cases fit *D***0** signal to extract *N***  **
- Use slow pion only to distinguish** ***B***0** from *B***+**
- 	(not in vertexing, K-factors etc., to avoid lifetime bias)

******(*B*+)/**(*B*0) = 1.093 ± 0.021(stat) ± 0.022(syst)

## B Decay Angular Amplitudes

- Uses *B*s *J*/** *** ; *Uses *B*d *J*/** *K**0
- Allows measurement of many parameters including polarization amplitudes and s = 1/**L – 1/**H

- CP odd
- CP even

## Transversity Angles

- The *J*/**rest frame
*KK* defines (*x*,*y*) plane
*K*+(*K*) defines +*y* direction
-   polar & azimuthal angles of **+
-  helicity angle of **(*K**)

- Extract polarization
- amplitudes:
*A*0: Longitudinal
*A*, *A*: Transverse

**Notes:**
Pseudoscalar to vector vector decays characterized by three polarization amplitudes.

## Angular Projections and fit for Bs

- Decay Angular Distribution:

**

## Bs Mass and Lifetime Projections

***L *= 1.05      ± 0.02 ps

- * *= 0.47      ± 0.01 ps–1* *

- = 0.65       ± 0.01

- +0.16
- –0.13

***H *= 2.07      ± 0.03 ps

- +0.58
- –0.46

- +0.19
- –0.24

- +0.25
- –0.33

- Unconstrained fit

* **m**s*= 125      ps–1* *

- Using SM and constrained fit:

- +65
- –55

## Bs and Bd Amplitudes

**For  *****B******d*****0**
*A*0 = 0.750 **±  **0.017  **± **0.012
*A*|| = (0.473 **±  **0.034  **± **0.006) ×
- 		       *e**i*(2.86 **± **0.22 **± **0.04)
- |*A****┴***| = (0.482 **±  **0.104 **± **0.014) ×
- 		       *e**i*(0.15 **± **0.15 **± **0.04)
**For  *****B******s*****0**
*A*0 = 0.784 **±  **0.039  **± **0.007
*A*|| = (0.510 **±  **0.082  **± **0.013)×
- 		        *e**i*(1.94 **± **0.36 **± **0.03)
- |*A****┴ ***| = 0.354 **±  **0.098  **± **0.003

- DØ results coming soon

## Conclusions

- DØ and CDF are measuring many properties of *B* hadrons that nicely complement those measured at “*B* factories”
- We expect 500 pb-1 by the end of the year
- More exciting results are expected even in the next few weeks