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R D ( ) Anomaly: A Model-Independent Collider Signature and Possible Hint for R -parity Violating Supersymmetry B HUPAL D EV Washington University in St. Louis W. Altmannshofer, BD and A. Soni, Phys. Rev. D 96 , 095010 (2017) [arXiv:1704.06659

SLIDE 1

RD(∗) Anomaly: A Model-Independent Collider Signature and Possible Hint for R-parity Violating Supersymmetry

BHUPAL DEV

Washington University in St. Louis

W. Altmannshofer, BD and A. Soni, Phys. Rev. D 96, 095010 (2017)

[arXiv:1704.06659 [hep-ph]] and in preparation.

SUSY 2017 TIFR, Mumbai

December 12, 2017

SLIDE 2

RD(∗) Anomaly

RD = B(B → Dτν) B(B → Dℓν) , RD∗ = B(B → D∗τν) B(B → D∗ℓν) (where ℓ = e, µ).

R(D)

0.2 0.3 0.4 0.5 0.6

R(D*)

0.2 0.25 0.3 0.35 0.4 0.45 0.5

BaBar, PRL109,101802(2012) Belle, PRD92,072014(2015) LHCb, PRL115,111803(2015) Belle, PRD94,072007(2016) Belle, PRL118,211801(2017) LHCb, FPCP2017 Average SM Predictions

= 1.0 contours

χ ∆

R(D)=0.300(8) HPQCD (2015) R(D)=0.299(11) FNAL/MILC (2015) R(D*)=0.252(3) S. Fajfer et al. (2012)

) = 71.6%

χ P( σ 4 σ 2

HFLAV

FPCP 2017

SM

[Talk by Giacomo Caria]

SLIDE 3

Outline

A model-independent way to test the anomaly using ATLAS and CMS A possible correlation of the anomaly with the Higgs naturalness R-parity violating Supersymmetry with light 3rd generation

SLIDE 4

Model-independent Collider Analysis ⟶

τ⁺

In a nut-shell, the anomalous behavior is in the basic process: b → cτν. This necessarily implies by crossing symmetry an analogous anomaly in g + c → bτν. Leads to a model-independent collider probe: pp → bτν.

SLIDE 5

Model-independent Collider Analysis ⟶

τ⁺

In a nut-shell, the anomalous behavior is in the basic process: b → cτν. This necessarily implies by crossing symmetry an analogous anomaly in g + c → bτν. Leads to a model-independent collider probe: pp → bτν.

SLIDE 6

Effective Operators

The effective 4-fermion Lagrangian for b → cτν in the SM is given by −Leff = 4GFVcb √ 2 (¯ cγµPLb) (¯ τγµPLντ) + H.c. Same Lagrangian gives rise to pp → bτν, but the rate is CKM-suppressed. Need not be the case in a generic NP scenario, which might be

bservable above the SM background at the LHC.

Various dimension-6 four-fermion operators possible: [Freytsis, Ligeti, Ruderman

(PRD ’15)]

OVR,L = (¯ cγµPR,Lb) (¯ τγµPLν) OSR,L = (¯ cPR,Lb) (¯ τPLν) . OT = (¯ cσµνPLb)(¯ τσµνPLν) .

SLIDE 7

Effective Operators

The effective 4-fermion Lagrangian for b → cτν in the SM is given by −Leff = 4GFVcb √ 2 (¯ cγµPLb) (¯ τγµPLντ) + H.c. Same Lagrangian gives rise to pp → bτν, but the rate is CKM-suppressed. Need not be the case in a generic NP scenario, which might be

bservable above the SM background at the LHC.

Various dimension-6 four-fermion operators possible: [Freytsis, Ligeti, Ruderman

(PRD ’15)]

OVR,L = (¯ cγµPR,Lb) (¯ τγµPLν) OSR,L = (¯ cPR,Lb) (¯ τPLν) . OT = (¯ cσµνPLb)(¯ τσµνPLν) .

SLIDE 8

SM Backgrounds

The direct pp → bτν is suppressed by |Vcb|2. In a realistic hadron collider environment, however, there are other potentially dangerous backgrounds.

pp → jW → jτν (j misidentified as b) pp → W → τν, with an ISR gluon → b¯ b and one b is lost pp → tj → bτνj and pp → tW → bτνjj, where the jet(s) are lost pp → b¯ bj, where one b is misidentified as a τ and the light jet is lost (i.e. misidentified as MET).

The mis-ID rates at the LHC typically are at the level of ∼ 1%. With basic trigger cuts pj,b,ℓ

> 20 GeV, / ET > 20 GeV, |ηj,b,ℓ| < 2.5 and ∆Rℓj,ℓb,jb > 0.4, we find the dominant contribution comes from pp → Wj and pp → b¯ bj. σSM(pp → bτν → bℓ + / ET) ∼ 50 pb at √s = 13 TeV LHC.

SLIDE 9

SM Backgrounds

The direct pp → bτν is suppressed by |Vcb|2. In a realistic hadron collider environment, however, there are other potentially dangerous backgrounds.

pp → jW → jτν (j misidentified as b) pp → W → τν, with an ISR gluon → b¯ b and one b is lost pp → tj → bτνj and pp → tW → bτνjj, where the jet(s) are lost pp → b¯ bj, where one b is misidentified as a τ and the light jet is lost (i.e. misidentified as MET).

The mis-ID rates at the LHC typically are at the level of ∼ 1%. With basic trigger cuts pj,b,ℓ

> 20 GeV, / ET > 20 GeV, |ηj,b,ℓ| < 2.5 and ∆Rℓj,ℓb,jb > 0.4, we find the dominant contribution comes from pp → Wj and pp → b¯ bj. σSM(pp → bτν → bℓ + / ET) ∼ 50 pb at √s = 13 TeV LHC.

SLIDE 10

SM Backgrounds

The direct pp → bτν is suppressed by |Vcb|2. In a realistic hadron collider environment, however, there are other potentially dangerous backgrounds.

pp → jW → jτν (j misidentified as b) pp → W → τν, with an ISR gluon → b¯ b and one b is lost pp → tj → bτνj and pp → tW → bτνjj, where the jet(s) are lost pp → b¯ bj, where one b is misidentified as a τ and the light jet is lost (i.e. misidentified as MET).

The mis-ID rates at the LHC typically are at the level of ∼ 1%. With basic trigger cuts pj,b,ℓ

> 20 GeV, / ET > 20 GeV, |ηj,b,ℓ| < 2.5 and ∆Rℓj,ℓb,jb > 0.4, we find the dominant contribution comes from pp → Wj and pp → b¯ bj. σSM(pp → bτν → bℓ + / ET) ∼ 50 pb at √s = 13 TeV LHC.

SLIDE 11

Signal Rate

We consider the dimension-6 NP operators OVR,L and OSR,L. For a typical choice gNP/Λ2 = (1 TeV)−2, the signal cross section for pp → bτν → bℓ + / ET of σV ≃ 1.1 pb (vector case) and σS ≃ 1.8 pb (scalar case), both at √s = 13 TeV LHC. Can directly probe mediator masses up to around 2.4 (2.6) TeV at 3σ CL in the vector (scalar) operator case with O(1) couplings at √s = 13 TeV LHC with L = 300 fb−1. The signal-to-background ratio can be significantly improved by using specialized selection cuts, e.g. pb

T > 100 GeV, Mbℓ > 100 GeV and /

ET> 100 GeV.

SLIDE 12

Signal Rate

We consider the dimension-6 NP operators OVR,L and OSR,L. For a typical choice gNP/Λ2 = (1 TeV)−2, the signal cross section for pp → bτν → bℓ + / ET of σV ≃ 1.1 pb (vector case) and σS ≃ 1.8 pb (scalar case), both at √s = 13 TeV LHC. Can directly probe mediator masses up to around 2.4 (2.6) TeV at 3σ CL in the vector (scalar) operator case with O(1) couplings at √s = 13 TeV LHC with L = 300 fb−1. The signal-to-background ratio can be significantly improved by using specialized selection cuts, e.g. pb

T > 100 GeV, Mbℓ > 100 GeV and /

ET> 100 GeV.

SLIDE 13

Kinematic Distributions

SM Vector Scalar 200 400 600 800 1000 2000 4000 6000 8000 10000 pT

l (GeV)

Normalized Evenets SM Vector Scalar 200 400 600 800 1000 2000 4000 6000 8000 10000 pT

b (GeV)

Normalized Evenets SM Vector Scalar 500 1000 1500 2000 2000 4000 6000 8000 10000 Mbl (GeV) Normalized Evenets SM Vector Scalar 200 400 600 800 1000 2000 4000 6000 8000 10000 MET (GeV) Normalized Evenets

SLIDE 14

Cut Efficiency

Cut Efficiency Observable value SM Signal Signal (GeV) background (Vector case) (Scalar case) 100 0.01 0.52 0.56 pℓ

50 0.10 0.78 0.82 30 0.44 0.92 0.94 100 0.13 0.99 0.33 pb

50 0.47 1.00 0.62 30 0.75 1.00 0.84 100 0.18 0.96 0.76 Mbℓ 50 0.63 0.99 0.94 30 0.88 1.00 0.98 100 0.01 0.54 0.70 / ET 50 0.09 0.70 0.86 30 0.29 0.79 0.92

SLIDE 15

Possible Hint for Natural SUSY with RPV

Anomaly involved 3rd generation of the SM. Speculation: May be related to Higgs naturalness? An obvious UV-complete candidate: Natural SUSY with light 3rd

generation. [Brust, Katz, Lawrence, Sundrum (JHEP ’12); Papucci, Ruderman, Weiler (JHEP ’12)]

Coupling unification still preserved, even with RPV.

104 107 1010 1013 1016 1019 10 20 30 40 50 60

Μ @GeVD 1êΑi

SM RPV3 MSSM

SLIDE 16

Explaining the RD(∗) Anomaly

Consider a minimal RPV SUSY setup with the λ′-couplings. L = λ′

ijk

νiL¯ dkRdjL + ˜ djL¯ dkRνiL + ˜ d∗

kR¯

νc

iLdjL

−˜ eiL¯ dkRujL − ˜ ujL¯ dkReiL − ˜ d∗

kR¯

ec

iLujL

+ H.c.

Leads to the effective 4-fermion interactions: [Deshpande, He (EPJC ’17)] Leff ⊃ λ′

ijkλ′∗ mnk

2m2

˜ dkR

νmLγµνiL¯ dnLγµdjL + ¯ emLγµeiL (¯ uLVCKM)n γµ

V†

CKMuL

− νmLγµeiL¯ dnLγµ

V†

CKMuL

j + h.c.
−

λ′

ijkλ′∗ mjn

2m2

˜ ujL

¯ emLγµeiL¯ dkRγµdnR , Contributes to RD(∗) at tree-level: b → bν → cτν.

SLIDE 17

Allowed Parameter Space

RD RSM

= RD∗ RSM

D∗

=

v2 2m2

˜ bR

Xc

, Xc = |λ′

333|2 + λ′ 333λ′ 323

Vcs Vcb + λ′

333λ′ 313

Vcd Vcb

Z couplings t decays direct searches BÆtn RD + RD * BÆpnn BÆKnn

500 600 700 800 900 1000 0.5 1.0 1.5 2.0

GeVL

333 1016 1012 108 106 105 500 600 700 800 900 1000 0.5 1.0 1.5 2.0

GeVL

333

0.01

1016 1012 108 106 105

500 600 700 800 900 1000 0.2 0.1 0.0 0.1 0.2

GeVL

313

0.01

500 600 700 800 900 1000 0.06 0.04 0.02 0.00 0.02 0.04 0.06

GeVL

323

0.05

500 600 700 800 900 1000 0.5 1.0 1.5 2.0

GeVL

333

= 0

1016 1012 108 106 105

500 600 700 800 900 1000 0.5 1.0 1.5 2.0

m b

R HGeVL

l333

l313

= -0.05 , l323

= 0.01

1016 1012 108 106 105

500 600 700 800 900 1000 0.2 0.1 0.0 0.1 0.2

GeVL

313

0.01

500 600 700 800 900 1000 0.06 0.04 0.02 0.00 0.02 0.04 0.06

GeVL

323

0.05

SLIDE 18

Explaining the RD(∗) Anomaly

SLIDE 19

Conclusion and Outlook

If the RD(∗) anomaly is true, we should find an anomaly in the high-energy signal of pp → bτν. Provides a model-independent high-pT test of the RD(∗) anomaly at the LHC. Since it involves the 3rd generation, the origin of the anomaly might be related to the Higgs naturalness problem. A specific scenario that addresses this issue: Natural SUSY with RPV. Common explanation of RD(∗) and RK(∗)?