Transcript Level 1 Calorimeter Trigger - University of Wisconsin

CKM Status
In this lecture, we
study the results
summarized in
this plot.
July 7, 2015
Sridhara Dasu, CKM Status
1
Quark Mixing : Unitarity
Mass eigen st ates Weak eigen stat es
In Standard Model CP violation is
due to single non-zero complex
phase of this matrix
 Quark Mixing
Cabibbo - Kobayashi- Maskawa (CKM)
d  Vud Vus Vub  d 
  
  

s

V
V
V
cs
cb  s 
   cd
  
  

b
V
V
V
   td
ts
tb  b 
Agreement amongst various
measurements of angles and
sides is crucial test of the
Standard Model
Unit ary matrix VubV  V V  V V  0
*
ud
*
tb td
a
|Vub / Vcb|
buln/bcln
g
July 7, 2015
*
cb cd
All but DMs (CDF/D0) are
accessible to BaBar
|Vtd / Vts|
Bd,s mixing: DMd / DMs
ByK
Sridhara Dasu, CKM Status
b
Clean
experiment/theory
2
The Standard Model CKM Matrix
Mass Eigenstate s  Weak Eigenstate s  Quark Mixing
VCKM
Vud
  Vcd

 Vtd
Vus
Vcs
Vts
Vub 
Vcb 

Vtb 
CKM Matrix
Complex matrix described by
3 real parameters +
1 complex phase
Wolfenstein parameterization:
Exploit hierarchy in magnitudes by using Cabibbo angle, l=sinqc
VCKM
 1  l2 / 2
l

l
1  l2 / 2

 Al 3 1  r  i  Al 2
Al 3 r  i 

Al 2


1
A, r,  are O(1)
CP Violation:
July 7, 2015
  0  no CPV from SM
Sridhara Dasu, CKM Status
3
Unitarity Triangle
Choice of parameters:
r  1  l 2 / 2 r
l, A, r and 
  1  l 2 / 2 
Unitarity : 1  R t  R u  0
At the 1% level:
Vus
l  Vus  sin q c
l  0.2205  0.0018
At the 2% level: Vcb
A  Vcb /l 2
A  0.83  0.06
| Vub | and | Vtd |
 r - plane

 r,  
a
Ru g
Rt
b
0, 0
1, 0 r

Vud Vub
2
2
iγ
Ru 


r


e

Vcd Vcb
Vtd Vtb
2
2
i b
Rt 


(
1

r
)


e

Vcd Vcb
*
g  arg Vub
, a    g  b
July 7, 2015
Sridhara Dasu, CKM Status
4
Weak B Decays Access to CKM Parameters
b
Wt
s,d
g
Rare Effective FCNC
July 7, 2015
Sridhara Dasu, CKM Status
5
B Mixing
Neutral B mesons can turn into their anti-particle
BsH 
BsL 
July 7, 2015
1 (| B  | B  )  CP  odd
s
s
2
1 (| B  | B  )  CP  even
s
s
2
Sridhara Dasu, CKM Status
6
B Mass & Lifetime Difference
• Second order weak diagram gives non-zero
matrix element
– In B  B
basis have a non-diagonal B H B
Hamiltonian
 M M 12  i   12 
H  *
 M 12
  *

M  2  12
 
• Recall
| BsH   12 (| Bs  | Bs  )
Eigenstates are:
L
1
| Bs  
1
2
M H , L  M  Re( M 12  2i 12 )
 H , L    2 Im( M 12  2i 12 )
July 7, 2015
(| Bs  | Bs  )
  ( L   H ) 
Dm / 2
D / 2
2
u, ct,
D  L  H
1

Unlike the case of neutral K mesons,
for B mesons DM is significant but D
is negligible.
Sridhara Dasu, CKM Status
7
B Mixing
Neutral B mesons can turn into their anti-particle
–
–
In SM described by “box diagrams” measure |Vts(d)|
D ms(d) = [GF2mt2 F(mt2/mW2)/62] mBs(d)f2Bs(d)BBs(d)|Vts(d)V*tb|2
Oscill. Freq.
From lattice
O(30%) error
July 7, 2015
Sridhara Dasu, CKM Status
~1
8
Bd & Bs Mixing
Measurement of
UT side
yields measurement of
with O(5%) theory
error
July 7, 2015
Sridhara Dasu, CKM Status
9
The Golden Channel
July 7, 2015
Sridhara Dasu, CKM Status
10
Time Dependent Measurements
July 7, 2015
Sridhara Dasu, CKM Status
11
The SLAC B-Factory
Design Luminosity:
3 x 1033 cm-2 s-1 (Reached in 2001)
Peak Luminosity:
9 x 1033 cm-2 s-1 (Reached in 2004)
July 7, 2015
Sridhara Dasu, CKM Status
12
e+ e–  b b
 
e
Signal: e  (4S )  BB
Continuum background:
e e  uu, dd, ss, cc,  
July 7, 2015
Sridhara Dasu, CKM Status
cont : B ~ 4.3 : 1
13
BaBar
g, 0 and e± ID
/K/p ID
m and KL ID
RPC problems overcome
Forward RPCs replaced (2002)
Barrel RPCs  LSTs (2004/6)
July 7, 2015
Sridhara Dasu, CKM Status
Charged Particle Tracking,
Vertex Reconstruction (Dt),
Low momentum particle ID dE/dx
14
Four Main Themes in B Physics
• CP Violation in B decays
– Due to interference of mixing and decay amplitudes (indirect)
– Due to decay amplitude interference (direct)
• Searches for and studies of rare decays
– Sensitive to physics beyond the Standard Model
• B decay rate to rare final states
• CP violation of rare decays - can be very sensitive
• Precision determination of CKM matrix elements
– Need to significantly improve in order to determine whether observed
CP violation is consistent with SM predictions
• Improving our understanding of B decays
– Feeds back into precision SM tests and measurements
July 7, 2015
Sridhara Dasu, CKM Status
15
Sin2b Measurement
(cc )KS0 (CP odd) modes
(cc )KL0 (CP even) modes
BABAR
Update for ICHEP04
BABAR
BABAR PUB-04/038
sin2b  0.722  0.040  0.023 (cc )K 0 + (cc )K 0
S
L
l  A / A  0.950  0.031  0.013
July 7, 2015
205fb 1 on peak or 227 M BB pairs
7730 CP events (tagged signal)
Sridhara Dasu, CKM Status
16
sin2b Comparison
CP violation in B system is almost
consistent with Standard Model
expectations
– Comparison of Tree and
Gluonic penguin
dominated decays provide
new physics sensitivity
• Curiously gluonic
penguin results are
systematically low
• More data is needed to
resolve experimental
discrepancies
• Do electroweak
penguin modes have
anything to say?
July 7, 2015
Sridhara Dasu, CKM Status
17
Electromagnetic Penguin
Penguins used for understanding the B-mesons:
Improves precision of Vub
u,d
b
W-
s,d
Vts,Vtd
t
g
B-meson
mass
Penguins used for measuring Vtd
B[ B  ( r /  )g ] Vtd

*
B[ B  K g ]
Vts
July 7, 2015
2
B-quark
mass
( m )  M B  mb ( m )
l1 (m )  m2 (m )
b-quark Fermi momentum
Sridhara Dasu, CKM Status
18
Photon Spectrum
Sum of exclusive method
Lepton tagged inclusive
preliminary
K*g
K*g
(4s) frame
B rest frame
July 7, 2015
Sridhara Dasu, CKM Status
19
Moments of g Spectrum
Penguins used for understanding the B-mesons:
Improves precision of Vub
First, Second moments of E
g
hep-ex/0506043
B-meson
mass
B-quark
mass
88 MB B
( m )  M B  mb ( m )
l1 (m )  m2 (m )
b-quark Fermi momentum
First and second moments of the photon spectrum
are used in heavy quark effective theory models.
July 7, 2015
Sridhara Dasu, CKM Status
20
Shape Function
HQ parametersdetermine shape function for Vub extraction
•
•
•
Fit to the Eg spectrum in bsg – Belle+Babar
Fit to the Eg moments of Eg spectrum - Babar
Had and lept. moments in bcln – Babar+others
Fit to all moments
Fit to bcln moments
Fit to b—sg moments
CKM-05
|Vcb| : moments analyses have 1.5–2% precision!
Vcb inclusive   42.0  0.6exp  0.8theo   103
Vcb exclusive   40.2  2.1exp  1.8theo   103
July 7, 2015
Sridhara Dasu, CKM Status
Belle b—sg
spectrum fit
21
|Vub |
The extraction of |Vub|from the
measured partial BFs is not trivial
– Inclusive decays depend on
measured shape function and
OPE
nonperturbative
corrections
free quark decay
2
d

~ V[u,c ]b   quark model 
d (PS)

Method
Cn
n
 
QCD
mb
4.39  0.20  0.27
Inclusive, Belle only bsg
spectrum
5.08  0.47  0.48
July 7, 2015
n



Vub(10-3)
Inclusive, bcln & bsg
moments
Indirectly, from CKM fit
Average of Inclusive Determinations of |Vub|
3.5300..22
21
Sridhara Dasu, CKM Status
More work needed to
resolve discrepancies
22
Standard Model Unitarity
Tree Level sin2b
– Consistent with SM
Progress requires
– Measurements of a,g
• Penguin pollution
Further checks of sin2b
– Measure in penguins
Measurement of sides
– Vub, Vtd
• Rare processes
• Hadronic uncertainty
• HeavyLight form
factor calculation
– Radiative penguins are
beginning to play an
important role in
constraining SM unitarity
July 7, 2015
Sridhara Dasu, CKM Status
23
Two Lifetimes
CP-odd fraction ( H) ~ 22%
 L  1.050.16
0.13  0.02 ps
-1
D s  0.470.19

0.01
ps
0.24
 H  2.07 0.58
0.46  0.03 ps
D s
 0.650.25
0.33  0.01
s
+ Recent D0:
July 7, 2015
 L  1.230.14
0.11 ps
 H  1.52
0.39
0.43
ps
D s
 0.210.27
0.40
s
Sridhara Dasu, CKM Status
 SL  1.42±0.04±0.06 ps
24