Quark-sector CP violations and beyond Youngjoon Kwon Yonsei - PowerPoint PPT Presentation

Quark-sector CP violations and beyond Youngjoon Kwon Yonsei University 1st T2HKK Workshop @ SNU, Nov. 21-22, 2016

Outline Introduction & Motivation CP violations in the quark sector Outlook 2

The three frontiers Flavor Physics 5 3

Energy vs. Intensity Frontiers Intensity Frontier is M NP [ TeV ] complementary to the Energy SuperKEKB 10 2 Frontier NP mass scale If LHC finds NP 10 KEKB * precision flavor input is essential to further clarify those discoveries LHC 1 Even if no new NP is found Tevatron * high-statistics flavor sector -1 10 2 measurements (on b , c , and τ ) can 1 10 10 (g NP /g) 2 provide beyond-TeV-scale probe for favor-violating coupling NP 4

Flavor Physics Grand Slam 5

Why interested in CP violations? Without CPV, we cannot exist. 1964 Cronin, Fitch, et al. • Discovery of CPV by observing 1967 A. Sakharov, 3 conditions • baryon # non-conservation • C & CP violation • not in thermal equilibrium 6

1/500 in 0.17 βγ 7

CPV in the Standard Model Kobayashi-Maskawa mechanism • provides CP violation within SM via quark mixing matrix (“CKM matrix”) in charged-current weak interactions • predicts large (~O(10%)) CP violations in the B 0 mesons • experimental tests of the unitarity of CKM matrix CP violations in the strong sector? 1 µ ν ˜ 16 π 2 F a F µ ν a L = θ Since neutrinos also mix (maximally), CPV in neutrinos is also a possibility; but no experimental signatures yet 8

Three ways for CPV in mixing M → X ℓ + ν ℓ ) − Ŵ ( M → X ℓ − ¯ A SL = Ŵ ( ¯ ν ℓ ) M → X ℓ + ν ℓ ) − Ŵ ( M → X ℓ − ¯ Ŵ ( ¯ ν ℓ ) in decays (“Direct CP violation”) W s t W g V ub via interference between mixing and decay ( t -dependent) f cp f cp B 0 = B 0 B 0 B 0 9

> 5 σ signatures of CPV (1) • Indirect CP violation in K → ππ and K → πℓν decays, and in the K L → π + π − e + e − decay, is given by | ϵ | = (2 . 228 ± 0 . 011) × 10 − 3 . (13 . 1) • Direct CP violation in K → ππ decays is given by R e ( ϵ ′ / ϵ ) = (1 . 65 ± 0 . 26) × 10 − 3 . (13 . 2) • CP violation in the interference of mixing and decay in the tree-dominated b → c ¯ cs transitions, such as B 0 → ψ K 0 , is given by (we use K 0 throughout to denote results that combine K S and K L modes, but use the sign appropriate to K S ): S ψ K 0 = +0 . 691 ± 0 . 017 . (13 . 3) first Belle-BaBar S D ( ∗ ) CP h 0 = +0 . 63 ± 0 . 11 , joint analysis 10

Belle, PRL (2012) 400 350 300 Events / 0.5 ps 250 200 150 100 50 0 0.6 0.4 Asymmetry 0.2 0 -0.2 -0.4 -0.6 -6 -4 -2 0 2 4 6 t (ps) ∆ 2008 11

CKM Unitarity Triangle fit (now) CKM fit (as of 2001) 12

> 5 σ signatures of CPV (2) S φ K 0 = + 0 . 74 +0 . 11 − 0 . 13 , S ψπ 0 = − 0 . 93 ± 0 . 15 , S η ′ K 0 = + 0 . 63 ± 0 . 06 , S D + D − = − 0 . 98 ± 0 . 17 . S f 0 K 0 = + 0 . 69 +0 . 10 − 0 . 12 , S D ∗ + D ∗− = − 0 . 71 ± 0 . 09 . S K + K − K S = + 0 . 68 +0 . 09 − 0 . 10 , 13

) 400 2 Events / (0.1) (a) Events / (0.0025 GeV/c (c) 3 10 350 300 250 2 10 200 150 100 10 50 Normalised Normalised 2 Residuals 2 Residuals 0 0 -2 -2 5.24 5.25 5.26 5.27 5.28 5.29 5.3 0 0.2 0.4 0.6 0.8 1 2 + M (GeV/c ) L bc K/ π q = +1 Events / (1.5 ps) (a) 300 q = -1 250 200 150 100 50 0 0 B B 0.5 (b) N N + - 0 0 0 B B N N -0.5 -7.5 -5 -2.5 0 2.5 5 7.5 t (ps) ∆ 14

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> 5 σ signatures of DCPV • Direct CP violation in the B 0 → K − π + mode is given by A B 0 → K − π + = − 0 . 082 ± 0 . 006 . (13 . 14) • Direct CP violation in B + → D + K + decays ( D + is the CP -even neutral D state) is given by A B + → D + K + = +0 . 195 ± 0 . 027 . (13 . 15) s → K + π − mode is given by • Direct CP violation in the B 0 s → K + π − = +0 . 26 ± 0 . 04 . (13 . 16) A B 0 • Direct CP violation in B + → K + K − π + decays is given by A B + → K + K − π + = − 0 . 118 ± 0 . 022 . (13 . 17) 16

The “K π puzzle” Belle, Nature 452, 20 (2008) a K – p + b K + p – 750 b a u W K + , p + 500 W s, d b s, d K + , p + u u b B + , B 0 g Entries per 2 MeV/ c 2 250 p 0 , p – B + , B 0 u u, d p 0 , p – u, d u, d u, d 0 d c c K − p 0 d K + p 0 300 u, d u b Z p 0 p 0 u, d u W b 200 d, s B + B + d, s p + , K + W p + , K + 100 u u u u 0 5.2 5.25 5.2 5.25 M bc (GeV/ c 2 ) A B 0 → K − π + = − 0 . 082 ± 0 . 006 , A B − → K − π 0 = 0 . 040 ± 0 . 021 from HFAG (2016) 17

CPV in Kaons: � ð K L ! � þ � � Þ = � ð K S ! � þ � � Þ E 7 3 1 7 . 4 ± 5.9 N A 3 1 2 3 . 0 ± 6.5 � ð K L ! � 0 � 0 Þ = � ð K S ! � 0 � 0 Þ ð ! Þ ð N A 4 8 1 4 . 7 ± 2.2 Þ � � � þ� 2 � � � 1 þ 6 Re ð � 0 = � Þ : � � ¼ � � � � K T E V 1 9 . 2 ± 2.1 Þ � � � 00 � � � � Trigger Muon Hodoscope Veto Drift Chambers CA (x10 -4 ) 0 10 20 30 CsI Regenerator 16.6 ± 2.3 N e w W o r l d A v e . 1 6 . 8 ± 1.4 Regenerator Beam Vacuum Beam Beams Mask Anti Photon Vetoes 25 cm Photon Vetoes Analysis Magnet Steel 120 140 160 180 Z = Distance from kaon production target (meters) 18

CPV in Kaons: PRL 101, 191802 (2008) BNL E787/E949 E787/E949 45 This analysis E949-PNN1 7 events observed 40 E787-PNN2 E787-PNN1 Simulation 35 Range (cm) • Not enough events to measure A CP 30 • contribution from intermediate 25 charm quark is not negligible, and 20 constitutes a source of hadronic uncertainty 15 10 High-precision results 50 60 70 80 90 100 110 120 130 140 150 expected from NA62 Energy (MeV) 19

CPV in Kaons: best limit by KEK E391 PHYSICAL REVIEW D 81, 072004 (2010) 0.4 0.35 0.3 (GeV/c) 0.25 0.2 KOTO goal T 0.15 P • to observe 3.5 SM signal in 3 years 0.1 running 0.05 0 200 250 300 350 400 450 500 550 600 Z (cm) vtx W )] 2 A 4 η 2 , B ( K L → π 0 νν ) = κ L [ X ( m 2 t /m 2 a very clean CPV mode to extract a CKM parameter η 20

CPV in charm a d � ∞ � ∞ f = 2 r f sin φ f sin δ f Γ ( D 0 Γ ( D 0 phys ( t ) → f ) dt − phys ( t ) → f ) dt 0 0 a f ≡ � ∞ � ∞ Γ ( D 0 Γ ( D 0 phys ( t ) → f ) dt + phys ( t ) → f ) dt �� � � � � a m = − y q p 0 0 � � � � cos φ D � − � � � � 2 p q � � � f = a d f + a m f + a i f �� � � � � a i = x q p � � � � � + sin φ D no evidence for charm CPV yet � � � � 2 p q � � � direct CPV can be isolated by ∆ a CP ≡ a K + K − − a π + π − = a d K + K − − a d π + π − LHCb, JHEP 1407, 041 (2014) 21

CPV in charm an honorable mention D þ ! K 0 S � þ ¼ ð� 0 : 363 � 0 : 094 � 0 : 067 Þ % . A CP Belle PRL 109, 021601 (2012) measurement supersedes our previous determination • the only evidence for CPV 5 10 0.005 ) 2 in charm sector Events/(1 MeV/c 0 + π • consistent with what’s S 0 K -0.005 → CP + D A expected from CPV in K 0 4 10 -0.01 1.8 1.9 0 2 + -0.015 M(K ) (GeV/c ) π 0 0.5 1 S CMS 5 0 10 ) 2 -0.01 Events/(1 MeV/c FB + D A -0.02 -0.03 4 10 -0.04 1.8 1.9 0 0.5 1 0 2 - M(K ) (GeV/c ) π c.m.s. S |cos | θ + D 22

CPV beyond the quark sector Why beyond? • CPV in quark sector is consistent with KM mechanism • NP contribution of O(0.1) can still be accommodated • But, CPV via KM is far smaller than BAU, by O(10 − 10 ) CP violations in leptons & leptogenesis • many people’s favorite hypothesis for BAU • one of main motivations for T2HKK CP violations via EDM • or does it call for an axion? 23

future prospects for CPV in quarks 24

the next Luminosity Frontier SuperKEKB is the next luminosity frontier 4 25

SuperKEKB SuperKEKB The super B -factory at KEK (2018 start) ● A planned 40-fold increase in luminosity over KEKB (target: 8x10 35 cm -2 s -1 instantaneous, 50ab -1 integrated), due to major upgrades: ○ “Nano-beam” scheme (below) ○ Doubled beam currents ○ (large number of upgrades to RF, magnet, vacuum, etc. systems) ● First turns Feb. 10, 2016! Exciting times! See Y. Onishi, ICHEP highlights, 8/08 3 12:10 26

Belle II Belle II major upgrades Belle II at ICHEP: Detectors : DEPFET: L. Andricek, Poster 8th 18:30 SVD: A. Paladino, Detector 4th 17:00 EMC: Y. Jin, Poster 6th 18:00 iTOP: A. Schwartz, Detector 6th 14:30 iTOP: K. Inami, Poster 6th 18:00 CPU: M. Schram, Computing 4th 12:50 Physics : Prospects: B. Fulsom, Flavor 5th 14:30 Dark: G. Inguglia, BSM 4th 17:40 Bottomonia: K. Miyabayashi, Poster 6th 18:00 5 27

Belle II milestones Phase 1 (Feb. 2016) • beam commissioning + beam background measurements Phase 2 (Dec. 2017) • Detector in place without VXD+PXD Phase 3 (Nov. 2018) • Full physics run 28

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Belle II vs. LHCb complementarity (or competition!) at a glance adapted from 30