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Transcript of Large Electroweak Penguin Effects in B and K physics Makiko Nagashima Dept. of Physics, NTU Dept. of...
Large Electroweak Penguin Effects in B and K physics
Makiko NagashimaMakiko Nagashima
Dept. of Physics, NTUDept. of Physics, NTU
Collider and New physics Mini-Workshop II
July 21- 22, National Taiwan University
Contents
Summer Institute Introductions of introduction …
CP Violation in B physics
Paper hep-ph/0503072 (W.S.Hou, M.N, A. Soddu)
Impact of 4th generation on B→Kπ Direct CP
Paper in preparation (W.S.Hou, M.N, A. Soddu)
4th generation scenario and K physics
Long Introduction
Neither just “the second letter of the alphabet” nor “a mark given to student’s work”…
Introductions of Introduction …
What is the B physics ?
Physics related to B meson containing (anti) bottom quark
Why B physics ...?What can we learn from B physics (experiments) ?
CP is violating (C: charge conjugation, P: parity)
Origin of CP Violation ?
We still don’t have any convincing solution
Better understanding
Close to the early universe (need High Energy experiment but cannot reach Ultra-HE…)
CPV in fundamental particle processes
TEST OF THE STANDARD MODEL (current understanding)SEARCH FOR NEW PHYSICS (we don’t know now)
Standard Model and CKM mechanism
3 generation
SU(2) doublet
SU(2) singlet
CKM matrix
Unitarity Triangle
3 mixing angles
1 CP phase+
B physics: comparable
K physics: one side would be too small
That is why B physics has succeeded in study of CP violation.
Determination of the Unitarity Triangle
One of the clues to test of SM / search for NP
Experimental result on DCPV of B→Kπ seemingly allow accommodations for the NP …
Parts of decay modes
Accumulation of dataExperiments tell us a lot !!
We can/must use all of them !!try to understand the physics behind them!!
Observables of CP Violation
Direct CP asymmetryDirect CP asymmetry
We focus on DCPV in this talk
see directly the difference of yield
Time dependent CP asymmetryTime dependent CP asymmetry
BB f
( Direct CPV )
( Mixing-induced CPV )
Only for neutral meson
(irrelevant to weak int.)
What is the indication of non-zero DCPV ?
Suppose the amplitude can be expressed in terms of,
for the anti-particle process, CPchange of the sign
(i) given by single term
(ii) no relative phases goes away
Simple explanation about TREE and PENGUIN diagrams
Tree diagram
su
u
d d
bW
b
u
u
u
u
s
W>1/Nc
b
d
W
g u
s
d
u
Penguin diagram
b
d
u
s
d
u
W
Z,γ>
sub-dominant
Large EW penguin from 4Large EW penguin from 4thth generation generation and and B physics and K physicsB physics and K physics
Why this indicates a riddle ?
QCDF (BBNS)
SM3
kT PQCD (KLS)
away
sub-dominantcan be negligible
No Phase differences between them !!
Theoretical expectations within different treatment of the hadronic matrix element
(2003) (2001) contradiction
extra comparable contributionsbringing phase differencestoward
We call for Large with an extra weak phase
We employ kTPQCD approach
We saw that …
must not be negligible
How to explain the deviation ?
Assemble
4th generation scenariopenguinNew physics
consistent with ~12%
A. Arhrib and W-S. Hou, EPJC27,555
T. Yanir, JHEP06, 044
Minimum Setup
4th generation scenario
A sequential 4th generation in addition to the SM particles
well-known
unknown
same quantum number
follows WS parameterization
Effective Hamiltonian
Tree
QCD Penguin
EW/EM Penguin
t' effects well-satisfy b → sγrate and DCPV
Large enhancement
Wilson coefficient
Dividing ΔCi by QCD penguin
Constraint
PDG04
PDG04
Belle(04)
B(b→sll) gets greatly enhanced
Δm is lower than EXP. bound
4th generation effects are not excluded!!
Result
kTPQCD in the SM
4th generation+
sizable splitting between
Roughly,
described as
It naturally generates the phase diff. and sizable mag. of the extra term
Confess …..
Naively assumeddid not care about
One may have suspicion that b→s would spill over into s→d is not necessarily ~ 0
Our result is at leading order in kTPQCD.A recent result finds a much larger color-suppressedtree (C) at next-to-leading order. (talk by S. Mishima at Super B WSII, Hawaii April 2005)
should be all intertwined …
From previous study
W.S. Hou et al.PLB 192 441 (1987)
We need to deal with the mixing matrix in detail
Constraint on s ↔ d from K physics
Andrea’s talk at PPP6
(J. Bijnens et al.)
(E. Pallante et al.)
Therefore….
well-satisfy
Implication for
Current Upper Bound
It is very hard to measure but challenging…
The rate gets enhanced by almost two order of magnitude !!
is not in trouble (currently )
Summary
Introductions of Introduction B physics and CP ViolationKπ DCPV puzzle and 4th generation constraint from b→sll and Bs mixing kTPQCD + large EW effect4x4 mixing matrix and K physics constraints on s→d transition
Implication for
4th generation effects, constrained by B physics, are sizable in K physics.