flavored b-l model and b anomalies - resceu.s.u-tokyo.ac.jp filechengcheng han—-kavli ipmu b decay...

Chengcheng Han—-Kavli IPMU

Flavored B-L model and B anomalies

Chengcheng HanKavli IPMU

CosPA 2017Yukawa Institute for Theoretical Physics, Kyoto University, JAPAN

Based on arXiv:1705.03858(PLB), with Peter Cox and Tsutomu Yanagida


Outline

• Briefly overview the B anomaly

• The flavored B-L model and phenomenologies

• Summary and conclusions


B decay anomaly

KB

d

b s

l

l

LHCb arXiv:1705.05802RK =

Br(B ! Kµµ)

Br(B ! Kee)= 0.745+0.090

�0.074(stat)± 0.036((syst)

LHCb arXiv:1406.6482

[1, 6]

RK⇤ =Br(B ! K⇤µµ)

Br(B ! K⇤ee)= 0.69+0.11

�0.07(stat)± 0.05((syst)[1, 6]

0.66+0.11�0.07(stat)± 0.024(syst)[0.05,1] =

Combined ~4sigma tension with SM(RSM=1)

LFU violation


SM contributionLe↵ =

4GFp2VtbV

⇤ts

�Cl

9Ol9 + Cl

10Ol10 + C⌫O⌫

�,

b

t

sWL L

t

Z, γ

l l

b sL L

Z, γ

l l

W

tb sL L

ll

t

W

ν

Ol9 =

↵

4⇡(s�µ bL)

�l�µl

�,

Ol10 =

↵

4⇡(s�µ bL)

�l�µ�

5l�,

Oij⌫ =

↵

2⇡(s�µ bL)

⇣⌫i�µ⌫

jL

⌘.

CSM9 ⇠ �CSM

10 ⇠ 4.1

EFT


New Physics

Le↵ =4GFp2VtbV

⇤ts

�Cl

9Ol9 + Cl

10Ol10 + CTOT + CSOS + . . .

�,

O(0)S =

e2

(4⇡)2[sPR(L)b][ll], O

(0)P =

e2

(4⇡)2[sPR(L)b][l�5l],

OT =e2

(4⇡)2[s�µ⌫b][l�

µ⌫ l], OT5 =e2

(4⇡)2[s�µ⌫b][l�

µ⌫�5l].

O09 =

e2

(4⇡)2[s�µPRb][l�

µl], O010 =

e2

(4⇡)2[s�µPRb][l�

µ�5l],

Bobeth, Hiller, Piranishvili, ‘07


Fit results

Altmannshofer, Stangl & Straub, 1704.05435Geng, Grinstein, Jager, Martin Camalich, Ren & Shi,

1704.05446

A left hand coupling in the quark sector is preferred


New Physics interpretations

Z 0 Lepto-quark Loop

s�⇢bL µ�⇢µ


Scale of new physicsW. Almannshofer, Talk at Aspen, Jan. 2016


Questions?

Quark FCNC in the 2 heaviest families

Lepton Non-Universal interaction in the lightest 2 generations

If Z’, better same coupling to first 2 families,

Anomaly free?

Bunches of solutions


Flavored B-L

• Anomaly cancellation within one-generation

• Two Heavy right hand neutrinos still consistent with seesaw and leptogenesis

• No serious flavor changing neutral currents between first two generations

• B anomaly can be explained!

Only couple to third generation fermions


Couplings

T q =1

3

0

@0 0 00 0 00 0 1

1

A , T l =

0

@0 0 00 0 00 0 �1

1

A

Flavor eigenstate

Into mass eigenstate(we only assume left-hand mixing here)

TdL = U†dLT qUdL =

1

3

0

@0 0 00 s2✓q �s✓qc✓q0 �s✓qc✓q c2✓q

1

A

TeL = U†eLT

lUeL = �1

0

@0 0 00 s2✓l �s✓lc✓l0 �s✓lc✓l c2✓l

1

A

• To explain the B anomaly, we need opposite sign coupling with b-s and mu-mu,

• If assuming ✓q < 0

UdL = VCKM , it will give wrong sign!


LOW ENERGY Phenomenology

S =

Zd4x

⇢1

2Zµh

�@2 +M2

�Zh,µ � ghZ

µhJ

hµ

�

On-shellZh=

Zd4x

✓�1

2

g2hJ2

h

M2+O

�@2/M2

�◆

KB

d

b s

l

l

LFU violation processL = �

g2s✓qc✓qs2✓l

3M2(s�⇢bL)(µ�⇢µL) ,

�Cµ9 = ��Cµ

10 = � ⇡

↵p2GFVtbV ⇤

ts

g2s✓qc✓qs2✓l

3M2


Constraints

⌧

µ µ

µ

⌧ � µ cLFV

D0 � D0 mixingBs � Bs mixing

bL

sL bL

sL

uL

cL

cL

uL

L = �g2s2✓qc

2✓q

18M2(s�µbL)

2 � g2c2D18M2

(u�µcL)2 cD ⌘

�Vub c✓q � Vus s✓q

� �V ⇤cb c✓q � V ⇤

cs s✓q�

LLFV =g2

M2s3✓lc✓l ⌧ �

⇢µL µ�⇢µL


LHC dimuon resonance search

b

b

µ�

µ+

ATLAS-CONF-2017-027

No light quark(u,d) coupling, limit could be much weaker


Favored parameter space✓l =

⇡

2is assumed

✓q = �0.1

No landau pole before Mpl1�

2�

Z prime mass around few TeV LHC limit less than 2 TeV, could extend in the future to probe the z prime


Summary

❖ B anomaly may indicate a new gauge sector beyond SM

❖ This new gauge boson may also play the role of mediator of dark matter( see Peter Cox’s talk )

❖ Let us wait and see!


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flavored b-l model and b anomalies - resceu.s.u-tokyo.ac.jp filechengcheng han—-kavli ipmu b decay...

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