[PPT] - R ECENT RESULTS FROM LHCb A BRIEF SELECTION Patrick Spradlin on PowerPoint Presentation

SLIDE 1

RECENT RESULTS FROM LHCb

A BRIEF SELECTION Patrick Spradlin

n behalf of the LHCb collaboration

University of Glasgow Particle Physics

Fourth workshop on flavour symmetries and consequences in accelerators and cosmology (FLASY 2014) 17-21 June 2014, University of Sussex, Brighton, UK

P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 1 / 24

SLIDE 2

LHCb at the LHC

LARGE HADRON COLLIDER

P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 2 / 24

SLIDE 3

LHCb at the LHC

FORWARD ACCEPTANCE

Forward acceptance 2 < η < 5. Takes advantage of the predominant forward production of heavy flavored hadrons.

/4 π /2 π /4 π 3 π /4 π /2 π /4 π 3 π

[rad]

1

θ [rad]

2

θ

1

θ

2

θ b b

z

LHCb MC = 7 TeV s

1

η

8
6
4
2

2 4 6 8

2

η

8
6
4
2

2 4 6 8

LHCb acceptance GPD acceptance

= 7 TeV s LHCb MC

Pseudorapidity range unique among the LHC detectors. Complementary to the GPDs.

P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 3 / 24

SLIDE 4

LHCb at the LHC

LHCb detector

P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 4 / 24

SLIDE 5

LHCb at the LHC

LHCb beyond design

Exceeding design specifications to maximize physics reach Design 2012 Instantaneous luminosity,Linst ( cm−2 s−1) 2 × 1032 4 × 1032 Mean visible p-p interactions/crossing, µ 0.4 1.6 HLT output rate to tape ( kHz) 2 5

]

1

s

2

Luminosity [cm

32

10

33

10 Probability 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1 2 3 4 5 Design Operation

High rate heavy flavor production into LHCb acceptance: σvis

pp = 58.8 ± 0.2 mb

[JINST 7 (2012) P01010]

σbb,acc = 75.3 ± 14.1 µb

[PLB 694 209-216]

⇒ 30 kHz of bb production. σcc,acc = 1419 ± 134 µb

[Nucl.Phys.B 871, 1-20]

⇒ 600 kHz of cc production.

P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 5 / 24

SLIDE 6

LHCb at the LHC

TRIGGER STRUCTURE

40 MHz bunch crossing rate

450 kHz h± 400 kHz µ/µµ 150 kHz e/!

L0 Hardware Trigger : 1 MHz readout, high ET/PT signatures

Software High Level Trigger 29000 Logical CPU cores Offline reconstruction tuned to trigger time constraints Mixture of exclusive and inclusive selection algorithms 2 kHz Inclusive Topological

5 kHZ Rate to storage

2 kHz Inclusive/ Exclusive Charm 1 kHz Muon and DiMuon

Architecture and performance documented in JINST 8 (2013) P04022. Input includes 15 MHz of non-empty bunch crossings. L0 hardware trigger includes three main collections of channels Hadron calorimeter triggers, Muon detector triggers, Electromagnetic calorimeter triggers. HLT software trigger divided into two sequential stages HLT1: high-pT displaced tracks, 70 kHz retention. HLT2: full event reconstruction

P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 6 / 24

SLIDE 7

LHCb at the LHC

LHCb data collection 2010-2013

Data collection with pp collisions: 2010 38 pb−1 √s = 7 TeV, 2011 1.1 fb−1 √s = 7 TeV, 2012 2.0 fb−1 √s = 8 TeV. Data collection with pPb collisions: 2013 1.9 nb−1 √sNN = 5 TeV.

P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 7 / 24

SLIDE 8

LHCb at the LHC

LHCb physics program I

LHCb is designed for high precision searches for indirect evidence of New Physics beyond the Standard Model in Heavy meson mixing, e.g.,

φs in B0

s mixing,

AΓ in D0-D0 mixing.

CP violation, e.g.,

γ(φ3) in B decays, Direct CP violation in B and D decays.

Rare transitions of of b (and c) hadrons, e.g.,

Branching fractions of rare decays like B(s) → µ+µ−, AFB and angular analysis of B0 → K ∗0µ+µ− and related modes.

In these tasks, LHCb is performing admirably.

P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 8 / 24

SLIDE 9

LHCb at the LHC

LHCb physics program II

However, it is also an ideal laboratory for a much broader physics program, including Spectroscopy and the discovery of new states, Precision mass and lifetime measurements, Production measurements and precision tests of QCD, Precision branching fraction and decay amplitude measurements, including newly observed decay modes, Studies of proton–ion collisions at forward rapidities. Almost 200 papers submitted to journals This talk includes just a small selection of recent results

P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 9 / 24

SLIDE 10

Z(4430)+

Z(4430)− IN B0→ ψ′π−K +

PRL 112 222002 (2014)

]

2

[GeV

2

−

π ' ψ

m 16 18 20 22 )

2

Candidates / ( 0.2 GeV 500 1000

LHCb

]

2

[GeV

2

−

π

+

K

m 0.5 1 1.5 2 2.5 )

2

Candidates / ( 0.02 GeV 1 10

2

10

3

10

LHCb

Four-dimensional amplitude analysis of B0 → ψ′(µ+µ−)π−K + m2(K +π−), m2(ψ′π−), ψ′ helicity angle cos θψ′, and decay plane angle φ. 25176 ± 174 B0 → ψ′(µ+µ−)π−K + decays An order of magnitude more than previous analyses. Z(4430)− established at 13.9σ with properties m(Z) = 4475 ± 7+15

−25 MeV,

Γ(Z) = 172 ± 13+37

−34 MeV,

fZ = (5.9 ± 0.91.5

3.3)%,

JP = 1+, with other assignments ruled

ut at > 9σ.
P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 10 / 24

SLIDE 11

Z(4430)+

Z(4430)− IN B0→ ψ′π−K +

PRL 112 222002 (2014)

Model-independent analysis: Method of BaBar, PRD 79 112001 (2009) Legendre moments of K ∗ helicity angle distribution in slices of m(K +π−) , Reflect J ≤ 2 moments into the m(ψ′π−) distribution. K ∗ reflections unable describe the data.

[GeV]

−

π ' ψ

m 3.8 4 4.2 4.4 4.6 4.8 Efficiency corrected yield / ( 25 MeV ) 0.01 0.02 0.03 0.04

LHCb

−

Z

Re A

0.6
0.4
0.2

0.2

−

Z

Im A

0.6
0.4
0.2

0.2

LHCb

Replace Breit-Wigner amplitude model for Z(4430)− with six independent complex amplitudes in bins of m(ψ′π−) in the peak region, Tests phase variation with mass, Argand diagram shows rapid variation of phase at peak of magnitude, Consistent with resonance.

P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 11 / 24

SLIDE 12

AC

P IN D0 → h−h+ DECAYS

ACP IN D0→ h−h+ DECAYS

LHCb-PAPER-2014-013, ACCEPTED BY JHEP

Samples of D0 → K −K + and D0 → π−π+ produced in B → D0µ−νµX Charge of muon tags initial flavor of D0. Observed asymmetries a combination of CP asymmetry and confounding detection and production asymmetries. . . Araw = ACP + AD(µ−) + AP(B)

]

2

c [MeV/ )

+

K

−

M(K

1850 1900

)

2

c Candidates / ( 1.1 MeV/

20 40 60 80 100 120 140 160

3

10 ×

LHCb

Data Total Signal

Comb. bkg.

∼2 million D0 → K −K + decays Full 3 fb−1 Run 1 sample

. . . that cancel in the difference ∆ACP ≡ ACP(K −K +) − ACP(π−π+) = Araw(K −K +) − Araw(π−π+) Further, ACP(K −K +) can be extracted directly B → D0(K −π+)µ−νµX decays to cancel AD(µ−) + AP(B), Samples of promptly produced D+ → K −π+π+ and D+ → K 0π+ to measure the K −π+ detection asymmetry in the D0 → K −π+ sample ACP(K −K +) = Araw(K −K +) − Araw(K −π+) + AD(K −π+)

P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 12 / 24

SLIDE 13

AC

P IN D0 → h−h+ DECAYS

ACP IN D0→ h−h+ DECAYS

LHCb-PAPER-2014-013, ACCEPTED BY JHEP

ACP has contributions from direct and indirect CP violation. Indirect contribution dependent on mean D0 decay time of sample. ACP ≈ adir

CP − AΓ t τ t τ similar for K −K + and π−π+ samples

⇒ ∆ACP ≈ ∆adir

CP

]

2

c [MeV/ )

+

π

−

π M(

1800 1850 1900

)

2

c Candidates / ( 1.45 MeV/

10 20 30 40 50 60

3

10 ×

LHCb

Data Total Signal

Comb. bkg.

+

π

−

K → D

∼0.8 million D0 → π−π+ decays Full 3 fb−1 Run 1 sample

The most precise measurements of time-integrated CP asymmetries in D0 → h−h+ decays from a single experiment to date: ∆ACP = (+0.14 ± 0.16 ± 0.08) % ACP(K −K +) = (−0.06 ± 0.15 ± 0.10) % ACP(π−π+) = (−0.20 ± 0.19 ± 0.10) %

P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 13 / 24

SLIDE 14

C P VIOLATION IN B± → K +K −π± AND B± → π+π−π±

INCLUSIVE CPV IN B±→ K +K −π± AND B±→ π+π−π±

PRL 112 011801 (2014) First evidence of inclusive CP asymmetry in these modes: AC

P(K +K −π±) = −0.141 ± 0.040(stat) ± 0.018(syst) ± 0.007 (AC P(J/ψ K ±)) (3.2σ)

AC

P(π+π−π±) = 0.117 ± 0.021(stat) ± 0.009(syst) ± 0.007 AC P(J/ψ K ±) (4.9σ) (First evidence of C P asymmetry in 3-body charmless B decays in an earlier analysis of B± → K +K −K ±, PRL 111 (2013) 101801) ]

2

c [GeV/

−

π

−

π

+

π

m 5.1 5.2 5.3 5.4 5.5 × )

2

c Candidates / (0.01 GeV/ 100 200 300 400 500 600 700 800

(a) LHCb

]

2

c [GeV/

+

π

−

π

+

π

m 5.1 5.2 5.3 5.4 5.5 ×

model

±

π

−

π

+

π →

±

B combinatorial 4-body → B

−

π

+

π

±

K →

±

B

4904 ± 148 B± → π+π−π±, 1 fb−1 LHCb data ]

2

c [GeV/

−

π

−

K

+

K

m 5.1 5.2 5.3 5.4 5.5 × )

2

c Candidates / (0.01 GeV/ 100 200 300 400 500

(b) LHCb

]

2

c [GeV/

+

π

−

K

+

K

m 5.1 5.2 5.3 5.4 5.5 ×

model

±

π

−

K

+

K →

±

B combinatorial 4-body →

s

B 4-body → B

−

K

+

K

±

K →

±

B

−

π

+

π

±

K →

±

B

1870 ± 133 B± → K +K −π±, 1 fb−1 LHCb data

Observed asymmetry a combination of CP asymmetry and confounding detection and production asymmetries Araw = AC

P + AD(π±) + AP(B±)

AD(π±) previously measured AP(B±) from B± → J/ψ K ±

P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 14 / 24

SLIDE 15

C P VIOLATION IN B± → K +K −π± AND B± → π+π−π±

LOCAL CPV IN B±→ K +K −π± AND B±→ π+π−π±

PRL 112 011801 (2014)

B± → π+π−π±: large asymmetry in m2

π+π−high > 15 GeV2/c4 and

m2

π+π−low < 0.4 GeV2/c4.

B± → K +K −π±: large asymmetry in m2

K +K − < 1.5 GeV2/c4.

Regions of large asymmetry not clearly associated to resonances. Areg

CP(K +K −π±) = −0.648 ± 0.040(stat) ± 0.013(syst) ± 0.007 (ACP(J/ψK ±))

Areg

CP(π+π−π±) = 0.584 ± 0.082(stat) ± 0.027(syst) ± 0.007 (ACP(J/ψK ±))

P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 15 / 24

SLIDE 16

φs WORLD AVERAGE

φs AVERAGE WITH LHCb 1 fb−1 results

0.25 CDF LHCb ATLAS Combined SM 0.20 0.15 0.10 0.05 0-1.5

1.0
0.5

0.0 0.5 1.0 1.5 68% CL contours ( )

HFAG

PDG 2014

LHCb 1.0 fb

–1 + CDF 9.6 fb –1

+ ATLAS 4.9 fb

1

+ D 8 fb

– – 1

D Heavy Flavor Averaging Group

The CP-violating phase, φs, characterizing the interference between B0

s

mixing and decay in b→ ccs transitions. Sensitive to NP in mixing diagrams and penguin decay diagrams. SM: φSM

s

= −2 arg VtsV ∗

tb

VcsV ∗

cb = −0.0363+0.0016

−0.0015 rad [Charles et al., PRD 84 033005 (2011)]

World average with LHCb 1 fb−1: φs = 0.00 ± 0.07 rad

P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 16 / 24

SLIDE 17

φs IN B0

s → J/ψ π+π−

φs IN B0

s → J/ψπ+π−

LHCb-PAPER-2014-019, SUBMITTED TO PLB

) [MeV]

π

+

π ψ m(J/

5300 5400 5500

Combinations/ (5 MeV)

1000 2000 3000 4000 5000 6000 7000

LHCb

New measurement of φs in B0

s → J/ψπ+π− decays

27100 ± 200 B0

s → J/ψπ+π− candidates

with 79.6% purity in the full Run 1 3 fb−1. (Update to φs in B0

s → J/ψK +K − with

3 fb−1 is in preparation.) Time-dependent flavor-tagged amplitude fit that determines the CP content of the final state Independent variables: J/ψπ+π− mass, π+π− mass, three angles in the helicity basis, and decay time. Resonant components as in LHCb, LHCB-PAPER-2014-012 Same-side and opposite-side flavor tagging Decay time acceptance measured in B0 → J/ψK ∗0.

P. SPRADLIN (GLASGOW)

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SLIDE 18

φs IN B0

s → J/ψ π+π−

φs IN B0

s → J/ψπ+π−

LHCb-PAPER-2014-019, SUBMITTED TO PLB

Combinations/ (20 MeV)

500 1000 1500 2000 2500 3000 3500

) [GeV]

π

+

π m(

0.5 1 1.5 2

5

5

LHCb (a) Combinations/ 0.05

200 400 600 800 1000 1200

π

+

π

θ cos

1
0.5

0.5 1-5 5

LHCb (b) Combinations/ 0.05

200 400 600 800 1000 1200 ψ J/

θ cos

1
0.5

0.5 1-5 5

LHCb (c) ) π Combinations/ (0.1

200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400

χ

2
5

5

LHCb (d)

2

.

Allowing for direct CP violation that is common for all amplitudes: φs = 70 ± 68 ± 8 mrad |λ| = 0.89 ± 0.05 ± 0.01 Consistent with Standard Model prediction: φSM

s

= −36.3+1.6

−1.5 mrad [Charles et al., PRD 84 033005 (2011)]

P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 18 / 24

SLIDE 19

B0

s → µ+µ−

B0

s → µ+µ− IN LHC RUN 1

Evidence for B0

s → µ+µ− in LHCb and CMS

]

2

c [MeV/

−

µ

+

µ

m 5000 5500 )

2

c Candidates / (44 MeV/ 2 4 6 8 10 12 14 16 LHCb BDT>0.7

1

3 fb

LHCb: 4.0σ significance in 3 fb−1 [PRL 111, 101805 (2013)] B(B0

s → µ+µ−) =

2.9+1.1

−1.0

× 10−9

CMS: 4.3σ significance in 25 fb−1 [PRL 111, 101804 (2013)] B(B0

s → µ+µ−) =

3.0+1.0

−0.9

× 10−9
P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 19 / 24

SLIDE 20

B0

s → µ+µ−

B0

s → µ+µ− COMBINED RESULT

CMS-PAS-BPH-13-007, LHCb-CONF-2013-012

]

9 −

) [10

−

µ

+

µ →

s

B B( 2 4 6 8 10 12 14 16 18 20 22

preliminary CMS+LHCb

1 −

CMS 25fb

1 −

LHCb 3fb preliminary

1 −

ATLAS 4.9fb

1 −

CDF 10fb

1 −

D0 10.4fb

SM

]

10 −

) [10

−

µ

+

µ → B B( 1 2 3 4 5 6 7

preliminary CMS+LHCb

1 −

CMS 25fb

1 −

LHCb 3fb

1 −

CDF 10fb

SM

Naive combination of LHCb and CMS Run I measurements: B(B0

s → µ+µ−) = (2.9 ± 0.7) × 10−9

B(B0 → µ+µ−) =

3.6+1.6

−1.4

× 10−10

Consistent with SM predictions [Bobeth et al. PRL 112, 101801 (2014)] BSM(B0

s → µ+µ−) = (3.65 ± 0.23) × 10−9

Preliminary conclusions (thorough treatment in progress): B0

s → µ+µ− observed at > 5σ significance!

No statistically significant evidence for B0 → µ+µ−.

P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 20 / 24

SLIDE 21

B → K ∗µ+µ−

ANALYSIS OF B0→ K ∗0µ+µ−

]

4

c /

2

[GeV

2

q

5 10 15 20

]

2

GeV

4

c ×

7

[10

2

q /d B d

0.5 1 1.5

LHCb

Theory Binned LHCb

JHEP 08 (2013) 131, 1 fb−1 ]

4

c /

2

[GeV

2

q

5 10 15 20

'

5

P

1
0.8
0.6
0.4
0.2

0.2 0.4 0.6 0.8 1

SM Predictions Data

LHCb

PRL 111 (2013) 191801, 1 fb−1

Differential branching fraction, dB/dq2, and angular analysis [JHEP 08 (2013) 131] Four observables after angular folding : AFB: dimuon F-B asymmetry, FL: fractional K ∗0 polarization, S3: asymmetry related to the virtual photon polarization, A9: a CP asymmetry. Form-factor independent angular analysis [PRL 111 (2013) 191801] Observables with canceling form-factor uncertainties, 3.7σ discrepancy in P′

5.

Isospin asymmetry with B+ → K ∗+µ+µ− [LHCB-PAPER-2014-006]

P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 21 / 24

SLIDE 22

4

c /

2

< 6.0 GeV

2

q (c) 1.1 <

176 ± 17 B0 → K 0

S µ+µ− in 3 fb−1

Angular analysis of B+ → K +µ+µ− and B0 → K 0

S µ+µ− in bins of q2 to measure

AFB: forward-backward asymmetry (B+ → K +µ+µ− only) Approximately 0 in SM FH: fractional contribution of (pseudo)scalar and tensor amplitudes to the decay width Small in SM

P. SPRADLIN (GLASGOW)

RECENT RESULTS FROM LHCb FLASY 2014.06.19 22 / 24

SLIDE 23

B → K ∗µ+µ−

ANGULAR ANALYSIS OF B → Kµ+µ−

LHCb-PAPER-2014-007, SUBMITTED TO JHEP

B+ → K +µ+µ−

]

4

c /

2

[GeV

2

q

5 10 15 20

FB

A

0.2
0.1

0.1 0.2

LHCb

]

4

c /

2

[GeV

2

q

5 10 15 20

H

F

0.1 0.2 0.3 0.4 0.5

LHCb

B0 → K 0

S µ+µ−

]

4

c /

2

[GeV

2

q

5 10 15 20

H

F

0.5 1 1.5

LHCb

Consistent with SM predictions in every q2 bin. Constrains contributions from (pseudo)scalar and tensor amplitudes.

Figures show SM predictions from Bobeth et al., JHEP 01 (2012) 107

P. SPRADLIN (GLASGOW)

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SLIDE 24

SUMMARY

Exploitation of the full LHC Run 1 data set of 3 fb−1 at LHCb is underway and yielding some of the most precise measurements in the b and c sector. Only a fraction of our results were presented today, Many more measurements in progress. No deviations from the SM yet observed. LHC Run 2 projected to add 8 fb−1, allowing LHCb to find or rule-out large sources of flavour symmetry breaking at the TeV scale. An upgraded LHCb detector to operate during LHC Runs 3 and 4 is approved and in development, Up to 50 fb−1 Essential to match SM theory errors in many key measurements.

P. SPRADLIN (GLASGOW)

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