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Weak Charged Current Interactions. charm decay. neutrino scattering. f. ~. f. ~. f.

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weak charged current interactions
Weak Charged Current Interactions

charm decay

neutrino scattering

f

~

f

~

f

As a first approximation, the weak charged current interaction couples fermions of the same generation. The Standard Model explains couplings between quark generations in terms of the Cabibbo-Kobayashi-Maskawa (CKM) matrix.

Michael D Sokoloff

babar detector
BaBar Detector

All subsystems crucial for CPV analysis

SVT:97% efficiency, 15 mm z hit resolution (inner layers, transverse tracks)

SVT+DCH: (pT)/pT = 0.13 %  pT+ 0.45 %

DIRC: K- separation 4.2  @ 3.0 GeV/c  2.5  @ 4.0 GeV/c

EMC:E/E = 2.3 %E-1/4  1.9 %

Michael D Sokoloff

time dependent cpv at the 4s resonance

e+e-  (4S)  BB

m-

Flavor tag and vertex reconstruction

K-

Btag

m-

Brec

m+

B0

KS

B0

p+

Coherent L=1 state

p-

Start the Clock

Stop the Clock

Time-Dependent CPV at the (4S) Resonance

Boost: bg= 0.55

(4S)

Exclusive B meson and vertex reconstruction

Michael D Sokoloff

sin 2 b fit results summer 2002

}

|lf| = 0.948  0.051 (stat)  0.017 (syst) Sf = 0.759  0.074 (stat)  0.032 (syst)

hf =-1

sin(2b) Fit ResultsSummer 2002

hf =+1

hf =-1

sin2b = 0.755  0.074

sin2b = 0.723  0.158

sin2b = 0.741  0.067 (stat)  0.034 (sys) with

|lf| = 1

Michael D Sokoloff

the ckm matrix today
The CKM Matrix Today

Michael D Sokoloff

the 2008 nobel prize in physics
The 2008 Nobel Prize in Physics
  • “The broken symmetries described by Makoto Kobayashi and Toshihide Maskawa … seem to have existed in nature since the very beginning of the universe and came as a complete surprise when they first appeared in particle experiments in 1964. It is only in recent years that scientists have come to fully confirm the explanations that Kobayashi and Maskawa made in 1972. It is for this work that they are now awarded the Nobel Prize in Physics. They explained broken symmetry within the framework of the Standard Model, but required that the Model be extended to three families of quarks. These predicted, hypothetical new quarks have recently appeared in physics experiments. As late as 2001, the two particle detectors BaBar at Stanford, USA and Belle at Tsukuba, Japan, both detected broken symmetries independently of each other. The results were exactly as Kobayashi and Maskawa had predicted almost three decades earlier.”

Michael D Sokoloff

2010 dirac medal
2010 Dirac Medal

The 2010 Dirac Medal and Prize are awarded to Nicola Cabibbo (University La Sapienza, Rome, Italy) and Ennackal Chandy George Sudarshan (University of Texas, Austin, Texas, USA) in recognition of their fundamental contributions to the understanding of weak interactions and other aspects of theoretical physics.

Cabibbo’s important contributions to theoretical physics include the recognition of the significance of mixing in weak interactions, which has established the existence of a new class of physical constants, whose first example is the Cabibbo angle. This angle determines the mixing of strange quarks with non-strange quarks and has been measured experimentally. With the discovery of a third family of quarks and leptons, quark mixing led to the understanding of the phenomenon of CP violation.

Michael D Sokoloff

discovery of narrow d sj states 2003 primary decay modes do not conserve isospin
Discovery of Narrow DSJ States (2003)[primary decay modes do not conserve isospin]

Michael D Sokoloff

charm mixing time evolution of d 0 k decays

DCS

K+-

D0

CF

MIX

D0

Charm MixingTime-Evolution of D0K Decays

RS = CF

WS = DCS

DCS and mixing amplitudes

interfere to give a “quadratic”

WS decay rate (x, y << 1):

where

and  is the phase difference between DCS and CF decays.

Michael D Sokoloff

simplified fit strategy validation
Simplified Fit Strategy & Validation

Rate of WS events clearly increases with time:

(stat. only)

WS/RS (%)

Michael D Sokoloff

simplified fit strategy validation1
Simplified Fit Strategy & Validation

Rate of WS events clearly increases with time:

(stat. only)

WS/RS (%)

Inconsistent

with no-mixing

hypothesis:

2=24

Michael D Sokoloff

simplified fit strategy validation2
Simplified Fit Strategy & Validation

Rate of WS events clearly increases with time:

Consistent with

prediction from

full likelihood fit

2=1.5

(stat. only)

WS/RS (%)

Inconsistent

with no-mixing

hypothesis:

2=24

Michael D Sokoloff

time dependence in d 0 k s
Time-Dependence in D0 → KSπ+π-

box size is “capped” linear

box size is logarithmic

Theseplots illustrate the average decay time as a function of position in the Dalitz plot for (x,y) = (0.8%, 0.3%). The sizes of the boxes reflect the number of entries, and the colors reflect the average decay time.

Michael D Sokoloff

charm mixing today
Charm Mixing Today

Michael D Sokoloff

discovery of the h b 2008
Discovery of the hb [2008]

Michael D Sokoloff

slide18

Hard scattering amplitude for qq transition

which is calculable

in pQCD

Nonperturbative meson distribution amplitude describing the transition

P  qq

x: fraction of the meson momentum carried by one quark in the infinite momentum frame

Michael D Sokoloff

babar for bean counters
BaBar for Bean-Counters

Michael D Sokoloff

the beauty of superb
The Beauty of SuperB

Michael D Sokoloff

the charm of superb
The Charm of SuperB

480 fb-1

75 ab-1

Michael D Sokoloff