Alexey A. Petrov - Physics & Astronomy - Wayne State ...apetrov/Vanderbilt2011.pdf · Alexey A...
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Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Alexey A. PetrovWayne State University
Michigan Center for Theoretical Physics
1. Introductiona. Standard Model and why we love itb. Standard Model and why we hate it
2. Flavor-changing neutral currents and meson mixing3. Need for New Physics4. Conclusions
The physics of flavor
...with some help from S. Harris
Wednesday, September 21, 11
Flavour, also spelled flavor, in particle physics, property that distinguishes
different members in the two groups of basic building blocks of matter, the
quarks and the leptons. There are six flavours of subatomic particle within
each of these two groups: six leptons (the electron, the muon, the tau, the
electron-neutrino, the muon-neutrino, and the tau-neutrino), and six quarks
(designated up, down, charm, strange, top, and bottom).
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
What is “flavor”?
43
In this presentation I will mainly talk about quarks.
The secret of being a bore is to tell everything (Voltaire). Le secret d'ennuyer est celui de tout dire.
(consult Prof. T. Weiler about leptons)
Wednesday, September 21, 11
Why flavor?
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 201142Wednesday, September 21, 11
Why flavor?
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 201142Wednesday, September 21, 11
Why flavor?
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 201142Wednesday, September 21, 11
Why flavor?
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 201142Wednesday, September 21, 11
Why flavor?
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 201142Wednesday, September 21, 11
NSF CAREER award PHY-0547794
DOE grant DE-FG02-96ER41005
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 201141
Faculty Competition for Post-Doctoral Fellows
★ In case DOE reviewers of my grant are in the room, this work was really supported by...
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
1. Introduction
The Standard Model of particle physics is a remarkably simple and powerful construct
40Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
1. Introduction
The Standard Model of particle physics is a remarkably simple and powerful construct
40
Gauge symmetries: all particles are (initially) massless
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
The Ultimate Equation?
Something is needed to give masses to all particles
39Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
+
The Ultimate Equation?
Something is needed to give masses to all particles
39Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
+ Standard Model
The Ultimate Equation?
Something is needed to give masses to all particles
=
39Wednesday, September 21, 11
LSM =⇤
⇥
⇤�µ�i⌅µ �
g1
2YW Bµ �
g2
2⌦⇥L
⌦Wµ
⇥⇤ + LB, kin + LW, kin + LHiggs
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
+ Standard Model
The Ultimate Equation?
★ Part of the Lagrangian related to matter interaction with Higgs: flavor
Something is needed to give masses to all particles
=
39Wednesday, September 21, 11
m�
mµ� 17 ,
mµ
me� 207 .
Vud � 1, Vus � 0.2, Vcb � 0.04, Vub � 0.004
md
mu⇥ 2 ,
ms
md⇥ 21 ,
mt
mc⇥ 267 ,
mc
mu⇥ 431 ,
mt
mu⇥ 1.2� 105 .
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Matter sector: experimental data
38
★ Ratios of masses of quarks and leptons
- quarks
- leptons
★ Quark mixing (Cabibbo-Kobayashi-Maskawa) matrix parameters
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
A couple of questions...
Note that gauge forces in SM do not distinguish between fermions of different generations:
- e, µ, τ have same electrical charge- quarks have same color charge
★ Why generations? Why only 3? Are there only 3?★ Why hierarchies of masses and mixings?★ Can there be transitions between quarks/leptons
of the same charge but different generations?
37Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
A couple of questions...
Note that gauge forces in SM do not distinguish between fermions of different generations:
- e, µ, τ have same electrical charge- quarks have same color charge
★ Why generations? Why only 3? Are there only 3?★ Why hierarchies of masses and mixings?★ Can there be transitions between quarks/leptons
of the same charge but different generations?
The flavor puzzle
37Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Standard Model “solution”
36
1. Why generations? Why only 3? Are there only 3?
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Standard Model “solution”
36
1. Why generations? Why only 3? Are there only 3?
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Standard Model “solution”
36
1. Why generations? Why only 3? Are there only 3?
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Standard Model “solution”
35
1. Why generations? Why only 3? Are there only 3?‣ ???
2. Why hierarchies of masses and mixings?
3. Can there be transitions between quarks/leptons of the same charge but different generations?
L1 = �y�⇥̄L⇥R� + h.c.⇥ �y�v⇤2
�⇥̄L⇥R + ⇥̄R⇥L
⇥,
m� = y�v/�
2
No explanation of the hierarchy, but mass hierarchy is related to hierarchy of Yukawa couplings
No transitions at tree level (no interactions that change flavor w/out changing electric charge), but...
yu � 10�5, yc � 10�2, yt � 1,
yd � 10�5, ys � 10�3, yb � 10�2,
ye � 10�6, yµ � 10�3, y� � 10�2.
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
FCNC in the SM: GIM-mechanism
34
Let’s calculate them! For each internal quark type we get
There are no ΔQ=2 interactions in the Standard Model… … but we can make them via a “two-step process” (loop diagram):
(k2)
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
FCNC in the SM: GIM-mechanism
34
Let’s calculate them! For each internal quark type we get
There are no ΔQ=2 interactions in the Standard Model… … but we can make them via a “two-step process” (loop diagram):
(k2)
Divergent: not good...
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
GIM-mechanism
33
Thus, in the limit where k >> mi, mj, MW:
However, CKM matrix is unitary: contribution of different internal flavors comes with different signs!
top:
top-charm:
top:
top-charm:
… and similarly for other quarks
A ��
i
m2i (VisV
�ib)
2gk(m2i ) Glashow-Iliopulous-Maiani
(k2)
(k2)
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Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Experimental consequences of FCNC
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★ FCNC can be seen experimentally
- ΔF = 1 processes (b→sγ , c→uγ , etc)
- ΔF = 2 processes (BB-mixing, KK-mixing, DD-mixing)
M. Purohit
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Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
2. Basics of meson mixing
ΔQ=2: only at one loop in the Standard Model: possible new physics particles in the loop ΔQ=2 interaction couples dynamics of D0 and D0
Time-dependence: coupled Schrödinger equations
Diagonalize: mass eigenstates flavor eigenstates
Mass and lifetime differences of mass eigenstates:
31
|D(t)� =�
a(t)b(t)
⇥= a(t)|D0� + b(t)|D0�
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
2. Basics of meson mixing
ΔQ=2: only at one loop in the Standard Model: possible new physics particles in the loop ΔQ=2 interaction couples dynamics of D0 and D0
Time-dependence: coupled Schrödinger equations
Diagonalize: mass eigenstates flavor eigenstates
Mass and lifetime differences of mass eigenstates:
31
|D(t)� =�
a(t)b(t)
⇥= a(t)|D0� + b(t)|D0�
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Mixing: charm and beauty
mixing mixing
• intermediate down-type quarks• SM: b-quark contribution is negligible due to VcdVub
*
• (zero in the SU(3) limit)
• intermediate up-type quarks• SM: t-quark contribution is dominant
• (expected to be large)
1. Sensitive to long distance QCD2. Small in the SM: New Physics! (must know SM x and y)
1. Computable in QCD (*)2. Large in the SM: CKM!
(*) up to matrix elements of 4-quark operators
Falk, Grossman, Ligeti, and A.A.P.Phys.Rev. D65, 054034, 2002 2nd order effect!!!
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(hard) (easy)
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Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Lifetime differences in mesons
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This is “theoretical data”
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Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Lifetime differences in mesons
29
K
D
Bd
Bs
This is “theoretical data”
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Mixing in mesons
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This is “real data”
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Mixing in mesons
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K Bd
Bs
This is “real data”
Wednesday, September 21, 11
⇥MBs = 2 |M12| , ⇥�Bs =4Re (M12��
12)⇥MBs
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
id
dt
�Bq(t)Bq(t)
⇥=
⇤M � i
2�⌅
ij
�Bq(t)Bq(t)
⇥
Easy case: Bs system
Mixing parameters are sensitive probes of flavor physics
➡ Theoretical predictions?C.Liu, FPCP 2008
★ Time development of Bs system
★ Mixing parameters (concentrate on Bs)
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�21(Bs) =�
k
Ck(µ)mk
b
⇥Bs|O�B=2k (µ)|Bs⇤.
M12(Bs) =G2
F MBs
12⇥2M2
W (VtbV�ts)
2 �̂BS0(xt)f2Bs
B
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Bs system: Standard Model contributions
Both ΔMBs and ΔΓBs can be computed in the limit mb→∞:
∆MBs:
∆ΓBs:
A.Buras, M.Jamin, P.Weisz
+
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�21(Bs) = � G2F m2
b
12⇥(2MBs)(V �
cbVcs)2 [[F (z) + P (z)] ⇥Q⇤
+ [FS(z) + PS(z)] ⇥QS⇤ + �1/m + �1/m2�
Q = (b̄isi)V�A(b̄jsj)V�A, QS = (b̄isi)S�P (b̄jsj)S�P
Q̃ = (b̄isj)V�A(b̄jsi)V�A, Q̃S = (b̄isj)S�P (b̄jsi)S�P
⇥�Bs =�0.0005B + 0.1732Bs + 0.0024B1 � 0.0237B2 � 0.0024B3 � 0.0436B4
+ 2⇥ 10�5�1 + 4⇥ 10�5�2 + 4⇥ 10�5�3 + 0.0009�4 � 0.0007�5
+ 0.0002⇥1 � 0.0002⇥2 + 6⇥ 10�5⇥3 � 6⇥ 10�5⇥4 � 1⇥ 10�5⇥5
� 1⇥ 10�5⇥6 + 1⇥ 10�5⇥7 + 1⇥ 10�5⇥8
⇥(ps�1).
�Q⇥ = 21 + Nc
Ncf2
BsM2
BsB
⇥QS⇤ =1 � 2Nc
Nc
M4Bs
(mb + ms)2f2
BsBS
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Not so easy: SM contributions to ΔΓBs
ΔΓBs: a calculation yields:
★ ... with operators
★ ... so the result (up to 1/mb2) is:
A.Badin, F. Gabbiani, A.A.P. Phys. Lett. B653, 230 (2007)
WC (incl. pQCD corr): Beneke et al, Ciuchini et al
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}
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⇥MexpBs
= (117.0± 0.8)� 10�13 GeV
or xBs = ⇥MBs/�Bs = 26.2± 0.5.�M th
Bs= (117.1+17.2
�16.4)� 10�13 GeV
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
SM contributions to ΔΓBs
★ Compare to experimental measurements
24
Lifetime difference:
Mass difference:
A.Badin, F. Gabbiani, A.A.P. Phys. Lett. B653, 230 (2007)
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Why is ΔΓBs interesting?
★ Probes of NP phase in Bs mixing in Bs ➛ J/𝜓 𝜙
23
Standard Model: βs is tiny; NP: anything!
Standard Model wins again...R. Van Kooten, LP-2011
G. Raven, LP-2011
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Why is ΔΓBs interesting?
★ Probes of NP phase in Bs mixing in Bs ➛ J/𝜓 𝜙
23
Standard Model: βs is tiny; NP: anything!
Standard Model wins again...R. Van Kooten, LP-2011
G. Raven, LP-2011
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Difficult case: D-mixing
★ Predictions of x and y in the SM are complicated-second order in flavor SU(3) breaking-mc is not quite large enough for OPE
-x, y << 10-3 (“short-distance”)-x, y ~ 10-2 (“long-distance”)
★ Short distance:-assume mc is large
-combined ms, 1/mc, as expansions-leading order: ms2, 1/mc6!
★ Long distance:-assume mc is NOT large
-sum of large numbers with alternating signs, SU(3) forces zero!-multiparticle intermediate states dominate
H. Georgi; T. Ohl, …I. Bigi, N. Uraltsev;
J. Donoghue et. al.P. Colangelo et. al.
Falk, Grossman, Ligeti, Nir. A.A.P.Phys.Rev. D69, 114021, 2004
Resume: a contribution to x and y of the order of 1% is natural in the SM
22
A.A.P. hep-ph/0611361
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Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Experimental consequences of FCNC: charm
21
★ D-mixing predicted in the Standard Model...
★ ... and observed in 2007!
- no-mixing is excluded at 10.1σ
x = 0.63+0.19-0.20% y = 0.75 ± 0.12 %
HFAG 2011
- observations consistent with no-CP-violation
- |x| ~ [0.1%, 1%]
- y ~ 1%
Falk, Grossman, Ligeti, Nir. A.A.P.Phys.Rev. D69, 114021, 2004
Falk, Grossman, Ligeti, and A.A.P.Phys.Rev. D65, 054034, 2002
➡ Consistent with Standard Model!!!
Johns, Sheldon, Webster
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 201120
Since all FCNC cases are adequately described by the Standard Model contributions, do we need New Physics???
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Do we need to search for New Physics?
19
★ Standard Model has intrinsic problem related to Higgs mechanism (stabilization of quantum effects)
- BSM stabilization (e.g. SUSY), other mechanisms of EWSB
★ Standard Model does not have enough CP-violation to describe generation of baryon asymmetry
- need for BSM sources of CP-violation
★ Standard Model adequately describes experimental FCNC data, but does not provide solution to the flavor puzzle
- BSM solution to the flavor problem?
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 201118
Solutions to the flavor problem?
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Need for New Physics…
★ New Physics is needed!!!
★ But of what kind?★ Multi-Higgs/LR models? ★ Supersummetry (SUSY)?★ Large extra dimensions?★ Technicolor?★ Compositeness?★ … other weird theory?
★ Ultimately: strings, M-theory?
17Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 201116
Solutions to the flavor problem?
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
3. Need for New Physics
★ New Physics is needed!!!
★ But of what kind?★ Multi-Higgs/LR models? ★ Supersummetry (SUSY)?★ Large extra dimensions?★ Technicolor?★ Compositeness?★ … other weird theory?
★ Ultimately: strings, M-theory?
BUT: flavor is mainly an INPUT, not OUTPUT of models
15Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Solutions to the flavor problem?
14
★ Standard Model adequately describes experimental FCNC data, but does not provide solution to the flavor puzzle
- BSM solution to the flavor problem?
- study FCNC (ΔF=2 and ΔF=1 processes) to get a glimpse of NP
Standard Model Supersymmetric SM
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Solutions to the flavor problem?
14
★ Standard Model adequately describes experimental FCNC data, but does not provide solution to the flavor puzzle
- BSM solution to the flavor problem?
- study FCNC (ΔF=2 and ΔF=1 processes) to get a glimpse of NP
or
Standard Model Supersymmetric SM
or ???
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
How does New Physics affect x and y in charm?
Local ΔC=2 piece of the mass matrix affects x:
13
Double insertion of ΔC=1 affects x and y:
Example:
Suppose
Amplitude
phase space
Golowich, Pakvasa, A.A.P.Phys. Rev. Lett.98:181801, 2007
Wednesday, September 21, 11
µ � 1 TeV µ � 1 GeV
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
How does New Physics affect x and y in charm?
Local ΔC=2 piece of the mass matrix affects x:
13
Double insertion of ΔC=1 affects x and y:
Example:
Suppose
Amplitude
phase space
Golowich, Pakvasa, A.A.P.Phys. Rev. Lett.98:181801, 2007
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
How does New Physics affect x and y in charm?
Local ΔC=2 piece of the mass matrix affects x:
13
Double insertion of ΔC=1 affects x and y:
Example:
Suppose
Amplitude
phase space
Golowich, Pakvasa, A.A.P.Phys. Rev. Lett.98:181801, 2007
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
How does New Physics affect x and y in charm?
Local ΔC=2 piece of the mass matrix affects x:
13
Double insertion of ΔC=1 affects x and y:
Example:
Suppose
Zero in the SU(3) limitFalk, Grossman, Ligeti, and A.A.P.Phys.Rev. D65, 054034, 2002 2nd order effect!!!
Amplitude
phase space
Golowich, Pakvasa, A.A.P.Phys. Rev. Lett.98:181801, 2007
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
How does New Physics affect x and y in charm?
Local ΔC=2 piece of the mass matrix affects x:
13
Double insertion of ΔC=1 affects x and y:
Example:
Suppose
Zero in the SU(3) limitFalk, Grossman, Ligeti, and A.A.P.Phys.Rev. D65, 054034, 2002 2nd order effect!!!
Can be significant!!!
Amplitude
phase space
Golowich, Pakvasa, A.A.P.Phys. Rev. Lett.98:181801, 2007
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 201112
Global Analysis of New Physics: ΔC=2
Multitude of various models of New Physics can affect x
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 201111
If all of those models of New Physics affect FCNC processes, how come all of them are described by the Standard Model so well???
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 201111
If all of those models of New Physics affect FCNC processes, how come all of them are described by the Standard Model so well???
The “New Physics” flavor puzzle
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Global Analysis of New Physics: ΔC=2
10
Let’s write the most general ΔC=2 Hamiltonian
… with the following set of 8 independent operators…
RG-running relate Ci(m) at NP scale to the scale of m ~ 1 GeV, where ME are computed (on the lattice) Each model of New Physics
provides unique matching condition for Ci(LNP)
E.Golowich, J. Hewett, S. Pakvasa and A.A.P.Phys. Rev. D76:095009, 2007
Wednesday, September 21, 11
+
�⇧
⇤
L�R
⇥⌃
⌅ +H�C=2NP =
1�2
NP
8�
i=1
zi(µ)Q�i
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Example: generic restrictions on FCNC from DD-mixing
★ Comparing to experimental value of x, obtain constraints on FCNC in charm sector- assume x is dominated by New Physics - assume no accidental strong cancellations b/w SM and NP
9
★ ... which are
�NP ⇤ (4� 10)⇥ 103 TeV
�NP ⇤ (1� 3)⇥ 102 TeV
Gedalia, Grossman, Nir, PerezPhys.Rev.D80, 055024, 2009
New Physics is either at a very high scales
tree level:
loop level:
or have highly suppressed couplings to charm!
★ Constraints on particular NP models available E.Golowich, J. Hewett, S. Pakvasa and A.A.P.Phys. Rev. D76:095009, 2007
Wednesday, September 21, 11
�NP ⇤ (4� 10)⇥ 103 TeV
�NP ⇤ (1� 3)⇥ 102 TeV
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Imaginary parts (CP-violation)
8
★ Assume that direct CP-violation is absent ( )- experimental constraints on x, y, ϕ, |q/p| exist
- can obtain generic constraints on Im parts of Wilson coefficients
Gedalia, Grossman, Nir, PerezPhys.Rev.D80, 055024, 2009
★ In particular,
New Physics is either at a very high scales
tree level:
loop level:
or have highly suppressed couplings to charm!
★ Constraints on particular NP models possible as well
H�C=2NP =
1�2
NP
8�
i=1
zi(µ)Q�i
Bigi, Blanke, Buras, Recksiegel,JHEP 0907:097, 2009
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
New Physics in x: lots of extras
Extra gauge bosons
7
Extra scalars
Extra fermions
Extra dimensions
Extra symmetries
Left-right models, horizontal symmetries, etc.
Two-Higgs doublet models, leptoquarks, Higgsless, etc.
4th generation, vector-like quarks, little Higgs, etc.
Universal extra dimensions, split fermions, warped ED, etc.
SUSY: MSSM, alignment models, split SUSY, etc.
E.Golowich, J. Hewett, S. Pakvasa and A.A.P.Phys. Rev. D76:095009, 2007
New Physics contributions do not suffer from QCD uncertainties as much as SM contributions since they are short-distance dominated.
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
New Physics in x: lots of extras
Extra gauge bosons
7
Extra scalars
Extra fermions
Extra dimensions
Extra symmetries
Left-right models, horizontal symmetries, etc.
Two-Higgs doublet models, leptoquarks, Higgsless, etc.
4th generation, vector-like quarks, little Higgs, etc.
Universal extra dimensions, split fermions, warped ED, etc.
SUSY: MSSM, alignment models, split SUSY, etc.
Total: 21 models considered
E.Golowich, J. Hewett, S. Pakvasa and A.A.P.Phys. Rev. D76:095009, 2007
New Physics contributions do not suffer from QCD uncertainties as much as SM contributions since they are short-distance dominated.
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Dealing with New Physics-I
6
Consider an example: FCNC Z0-boson
1. Integrate out Z: for µ < MZ get
appears in models with extra vector-like quarks little Higgs models
2. Perform RG running to µ ~ mc (in general: operator mixing)
3. Compute relevant matrix elements and xD
4. Assume no SM - get an upper bound on NP model parameters (coupling)
Wednesday, September 21, 11
HRS =2�krc
3M21
g2s (C1(Mn)Q1 + C2(Mn)Q2 + C6(Mn)Q6)
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Dealing with New Physics - II
5
Consider another example: warped extra dimensions
1. Integrate out KK excitations, drop all but the lightest
FCNC couplings via KK gluons
2. Perform RG running to µ ~ mc
3. Compute relevant matrix elements and xD
x(RS)D =
g2s
3M21
f2DBDMD
�D
�23[C1(mc) + C6(mc)]�
16C2(mc)�
512
C3(mc)⇥
HRS =g2
s
3M21
(C1(mc)Q1 + C2(mc)Q2 + C3(mc)Q3 + C6(mc)Q6)
Constrains LHC parameter space!!!
Wednesday, September 21, 11
HRS =2�krc
3M21
g2s (C1(Mn)Q1 + C2(Mn)Q2 + C6(Mn)Q6)
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Dealing with New Physics - II
5
Consider another example: warped extra dimensions
1. Integrate out KK excitations, drop all but the lightest
FCNC couplings via KK gluons
2. Perform RG running to µ ~ mc
3. Compute relevant matrix elements and xD
x(RS)D =
g2s
3M21
f2DBDMD
�D
�23[C1(mc) + C6(mc)]�
16C2(mc)�
512
C3(mc)⇥
HRS =g2
s
3M21
(C1(mc)Q1 + C2(mc)Q2 + C3(mc)Q3 + C6(mc)Q6)
Implies: M1KKg > 2.5 TeV!
Constrains LHC parameter space!!!
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Summary: New Physics in mixing
Considered 21 well-established models
Only 4 models yielded no useful constraints
E.Golowich, J. Hewett, S. Pakvasa and A.A.P.Phys. Rev. D76:095009, 2007
4
A.A.P. and G. YeghiyanPhys. Rev. D77:034018, 2008
★ Flavor physics provides good constraints on New Physics models!
★ ... especially if used in correlation with other measurements!
E.Golowich, J. Hewett, S. Pakvasa and A.A.P.Phys. Rev. D79: 114030, 2009
Golowich, Pakvasa, A.A.P.Phys. Rev. Lett. 98:181801, 2007
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
So, what about models of flavor?
3
★ Proposed BSM solutions to the flavor problem
- continuous flavor symmetries- discrete flavor symmetries- accidental flavor symmetries
★ Dynamical mechanisms
- two-Higgs doublet models: tanβ as a large parameter
SM Lagrangian is U(3)5-invariant in the limit yi → 0
- Yukawas arise as a result of spontaneous breaking of a subgroup of U(3)5?
A. Blechman, A.A.P., G. YeghiyanJHEP 1011:075, 2010
★ Work is still continuing! LHC?
(consult Prof. T. Kephart about flavor models)
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Flavor as a probe of New Physics: anomalies?
2
Simplest decay of heavy-flavored meson: B ➛ τ𝜈
Only one non-perturbative parameter fBs = 250(12) MeV (~5%)
Harbinger of New Physics?
Two-Higgs doublet model:
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Before we conclude:
1
★ Are there more than three generations of quarks?
H. Bachacou, LP-2011
Higgs production at LHC is via gg ➛ H - extremely sensitive to 4th
generation quarks
H
g
g
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Before we conclude:
1
★ Are there more than three generations of quarks?
Sequential 4th generation is in trouble...
H. Bachacou, LP-2011
Higgs production at LHC is via gg ➛ H - extremely sensitive to 4th
generation quarks
H
g
g
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
4. Conclusions
Flavor puzzle is still a big problem for particle physics– The reason(s) for generations and mass hierarchy are not known– Standard Models simply parameterizes the solution– New Physics models use flavor as input, not output
Flavor-changing neutral current transitions provide great opportunities for studies of flavor in the SM and BSM– several anomalies in Bs physics might point to New Physics “around the corner”– studies of charmed transitions experience explosive growth
• unique access to up-type quark sector• large available statistics/in many cases small SM background • D-mixing is a second order effect in SU(3) breaking (x,y ~ 1% in the SM)• large contributions from New Physics are possible, but not seen
Maybe flavor physics will be the first to see glimpses of New Physics Maybe flavor physics will be the only game in town to see New Physics...
0Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Thank you for your attention!
0Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Thank you for your attention!
0
Hopefully, I did better than him...
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Additional slides
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Full Standard Model contains CP violation!
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Conditions for the asymmetry
Baryon (and lepton) number - violating processes
to generate asymmetry
Universe that evolves out of thermal equilibrium
to keep asymmetry from being washed out “Microscopic CP-violation”
to keep asymmetry from being compensated in the “anti-world”
Matter-antimatter imbalance in the UniverseA.D. Sakharov
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
2. What is CP(T)?
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
2. What is CP(T)?
P: parity (inversion of space)
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
2. What is CP(T)?
P: parity (inversion of space)
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
2. What is CP(T)?
P: parity (inversion of space)
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
2. What is CP(T)?
P: parity (inversion of space)
C: charge conjugation
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
2. What is CP(T)?
P: parity (inversion of space)
C: charge conjugation
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
2. What is CP(T)?
P: parity (inversion of space)
C: charge conjugation
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
2. What is CP(T)?
P: parity (inversion of space)
C: charge conjugation
T: time reversal
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
2. What is CP(T)?
P: parity (inversion of space)
C: charge conjugation
T: time reversal
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
2. What is CP(T)?
P: parity (inversion of space)
C: charge conjugation
T: time reversal
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
Can Standard Model violate CP?
Strong and electromagnetic interactions conserve C, P and T
All interactions (local QFT) conserve combination CPT
Weak interactions violate P and C… what about CP?
But: if SM contains operators with complex phases then there just might be CP violation in the Standard Model!
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
How to observe CP-violation?
I. Intrinsic particle properties electric dipole moments:
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
How to observe CP-violation?
I. Intrinsic particle properties electric dipole moments:
Low energy strong interaction effects might complicate predictions!
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
5. CP-violation (preliminary)
16
In any quantum field theory CP-symmetry can be broken1. Explicitly through dimension-4 operators (“hard”)
Example: Standard Model (CKM):
2. Explicitly through dimension <4 operators (“soft”)
Example: SUSY
3. Spontaneously (CP is a symmetry of the Lagrangian, but not of the ground state)
Example: multi-Higgs models, left-right models
These mechanisms can be probed in charm transitions
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
CP-violation in charmed mesons Possible sources of CP violation in charm transitions:
CPV in Δc = 1 decay amplitudes (“direct” CPV)
CPV in mixing matrix (Δc = 2)
CPV in the interference of decays with and without mixing
15
One can separate various sources of CPV by customizing observables
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
A comment
14
Generic expectation is that CP-violating observables in the SM are small
Δc = 1 amplitudes Δc = 2 amplitudes
The Unitarity Triangle for charm:
Penguin amplitude
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
A comment
14
With b-quark contribution neglected: only 2 generations contribute real 2x2 Cabibbo matrix
Any CP-violating signal in the SM will be small, at most O(VubVcb*/VusVcs
*) ~ 10-3
Thus, O(1%) CP-violating signal can provide a “smoking gun” signature of New Physics
Generic expectation is that CP-violating observables in the SM are small
Δc = 1 amplitudes Δc = 2 amplitudes
The Unitarity Triangle for charm:
Penguin amplitude
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
How to observe CP-violation?
13
There exists a variety of CP-violating observables
1. “Static” observables, such as electric dipole moment
2. “Dynamical” observables:
a. Transitions that are forbidden in the absence of CP-violation
b. Mismatch of transition probabilities of CP-conjugated processes
c. Various asymmetries in decay distributions, etc.
Depending on the initial and final states, these observables can be affected by all three sources of CP-violation
Wednesday, September 21, 11
D0D0 � (F1)(F2)�(3770)� D0D0 � (CP±)(CP±)
CP [F1] = CP [F2]
�F1F2 =�F1�F2
R2m
⇤�2 + x2 + y2
⇥|�F1 � �F2 |2 +
�x2 + y2
⇥|1� �F1�F2 |2
⌅
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
a. Transitions forbidden w/out CP-violation
★ Recall that CP of the states in are anti-correlated at ψ(3770):★ a simple signal of CP violation:
★ CP-violation in the rate → of the second order in CP-violating parameters.★ Cleanest measurement of CP-violation!
CP eigenstate F1
CP eigenstate F2
τ-charm factory
12
I. Bigi, A. Sanda; H. Yamamoto; Z.Z. Xing; D. Atwood, AAP
Wednesday, September 21, 11
DCP (+) � f1f2
Bl± =
�(DCP± � Xl�)�tot
y cos � =14
�Bl
+
Bl��
Bl�
Bl+
⇥
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
★ If CP violation is neglected: mass eigenstates = CP eigenstates★ CP eigenstates do NOT evolve with time, so can be used for “tagging”
KS
π0
CP Eigenstate (-)
f1
f2
★ τ-charm factories have good CP-tagging capabilities CP anti-correlated ψ(3770): CP(tag) (-1)L = [CP(KS) CP(π0)] (-1) = +1 CP correlated ψ(4140)
(-)
τ-charm factory (BES/CLEO-c)
Can measure (y cos φ): D. Atwood, A.A.P., hep-ph/0207165D. Asner, W. Sun, hep-ph/0507238
11
What if F1 or F2 is not a CP-eigenstate
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
b. Mismatch of transition probabilities
Look at charged D’s:
10
At least two components of the transition amplitude are required
Then, charge asymmetry will provide a CP-violating observable
…or, introducing rf=|A2/A1|:Prediction sensitive to details of hadronic model
Same formalism applies if one of the amplitudes is generated by New Physics
need rf ~ 1 % for O(1%) charge asymmetry
Wednesday, September 21, 11
Alexey A Petrov (WSU & MCTP) Vanderbilt U Colloquium, 22 September 2011
b. Mismatch of transition probabilities - II
Those observables are of the first order in CPV parameters, but require tagging
9
This can be generalized for neutral D-mesons too:
and
Each of those asymmetries can be expanded as
direct mixing interference
1. similar formulas available for f2. for CP-eigenstates: f=f and yf’ → y
Wednesday, September 21, 11