Belle II Physics and Construc4on Status
Tom Browder (University of Hawai’i at Manoa)
Complex phases in the weakinterac3on: Vtd and Vts andassociated CPV asymmetries
Excitement and High Stakes in
Flavor Physics:
1st TOP module arriving at Tsukuba Hall

-Connec4ons to the charged Higgs-Rare B Decays + NP

Flavor Physics, The Next
Genera3on: Belle II/SuperKEKB

1st DEPFET pixel plane

Apologies: I have borrowed slides from many excellent
physicists and will aim for “a big picture overview”
In ﬂavor physics but skip most details. BEAST results will
be covered by Nakayama-san.
1Feb 2016: First Turns at SuperKEKB (4 GeV e+’s and 7 GeV e-’s)

June 13, 2016 (LER beam current at 908 mA, HER at 828 mA)
2017: Collisions at the Υ(4S) will produce pairs of QM entangled (B-an4 B) mesons

First new particle collider since the LHC (intensity frontier rather
than energy frontier; e+ e- rather than p p)

Amplitudes and Phases in
the Weak Interac4on

N. Cabibbo

M.Kobayashi

T.Maskawato O(λ3)

L. Wolfenstein (1923-2015)3

Three Angles: (φ1,φ2,φ3) or (β, α, γ)Time dependentBàρπ Dalitz
analysis

B- àD

CP

K-

B0 à π- π+

LHCb results on CPV in
BsàDS-(*) K+

Unitarity implies that the
weak couplings and phases
form a triangle in thecomplex plane.

B0àΨ Ks,Ψ KL,
B0àD(*)0 h0

Big Ques4ons: Are determina3ons of angles consistent withdetermina3ons of the sides of the triangle ? Are angle
determina3ons from loop and tree decays consistent ?

4

Time-dependent CP viola4on is“A Double-Slit experiment” with par4cles and an4par4cles

QM interference between two diagramsbox diagram + tree diagram

tree diagram

b
d

c J/ψ
c
s K
S
d

b

Vtd
t
d

d

t

+
b

d
s
c
c

KS
J/ψ

Vtd
Measures the phase of Vtd or equivalently the phase of
Bd –anti Bd mixing.

5Measurement of sin(2φ1)/sin(2β) in BàCharmonium K0 modes

B0

J/ψKS

x= - 1(cc)KS

B0

J/ψKL

J/ψKL

x = +1

sin2φ 1=0.667±0.023±0.012
Af=0.006±0.016±0.012
PRL108,171802 (2012)

sin2φ1=0.687±0.028±0.012
Af=-0.024±0.020±0.016
PRD79,072009 (2009)

Overpowering evidence for CP viola4on (maner-an4maner
asymmetries). >>>> The phase of Vtd is in good agreement withStandard Model expecta4ons.
6 This is the phase of Bd mixing.

News from Utah, April 2016: APS Panofsky Prize
for Experimental Par3cle Physics Awarded to
Steve Olsen, Dave Hitlin, Jonathan Dorfan, and Fumihiko Takasaki“Founding Fathers of the B Factory Experiments”
A scene in Stockholm,
Sweden (2008)

Front row 2008 Physics Nobelists: T. Maskawa, M. Kobayashi

7B factories: High precision
CPV measurement and acalibra3on for NP.

2013: LHCb joins the game [±0.07(stat)]
2015: Latest LHCb measurement iscomparable in precision to B factories(now uses same-side B tagging)8

Results from Global Fits to Data (CKMFiner Group)
Great progress on ϕ3 or γ (ﬁrst from B
factories and now in the last three
years from LHCb).These measure

Similar results from UTFIT
as well from G. Eigen et al.
J. Charles et al, Phys. Rev.
D89 (2014) 033016

the phase of Vub

Wolfenstein Parameters

NP
Phase

Extrapola4on to 50 ab-1

NP/SM amplitude ra4o

Looks good(except for an issue with |Vub |)But a 10-20% NP amplitude in Bd
mixing is perfectly compa4blewith all current data.

9

BoxesAlthough B factories can run on
the Upsilon(5S), LHCb
dominates here

No phase expected from SM but
possible from NP par4cles

10Results on the phase of Bs-an4 Bs mixing(i.e. phase of Vts) [use BsàJ/ψϕ; J/ψππ modes]
Width
diﬀerence(Includes the most recent LHCb prelim
result, gives WA of -33 ±33 mrad)

Bs Mixing Phase11

BoxesNo phase expected from SM but
possible from NP par4cles

12

Phase of
Vts

K0

B0
13

New Physics Phases inPenguin bàs decays

No evidence for NP atcurrent level of sensi4vity
Bàη’ fromKS CPV
LHCb is absent
this game (lower KS eﬀ
and ﬂavor tagging eﬀ)
but dominates in BS
modes (Bsàϕϕ)
14

“Missing Energy” Decays

15

The BEH boson is now ﬁrmly
established by experimental resultsfrom ATLAS and CMS. Now planningfor future Higgs ﬂavor factory facili3es.
(e.g ILC, HL-LHC, CEPC, FCC).

Does the GP (BroutEnglert-Higgs par4cle)
have a “brother” i.e. thecharged Higgs ?
Y. Nambu, 1921-2015

Measurements at Belle II and direct searches at hadron colliders
take complementary approaches to this important ques4on.
16

Bàτ ν
(Decay with Large Missing Energy)

Sensi4vity to new
physics from acharged Higgs

W.S.Hou,. PRD 48, 2342 (1993)

The B meson decay constant, determined by the B
wavefunc3on at the origin(|Vub| taken from indep. measurements.)

17

Consumer’s guide to charged Higgs• Higgs doublet of type I (φ1 couples to upper (u-type) andlower (d-type) genera4ons. No fermions couple to φ2)• Higgs doublet of type II (φu couples to u type quarks, φdcouples to d-type quarks, u and d couplings are
diﬀerent; tan(β) = vu/vd) [favored NP scenario e.g.
MSSM, generic SUSY]• Higgs doublet of type III (not type I or type II; anythinggoes. “FCNC hell”àmany FCNC signatures)
Thanks to theorist Xerxes Tata

18

Why measuring B+àτ+ν is non-trivial
e+
BB-àX

ϒ(4S)

ντ

B+

νe

νe

Most of thesensitivity isfrom tau modes
with 1-prongs.

The experimental signature is rather difficult:
B decays to a single charged track + nothing(This may be hard at a hadron collider)19

Example of a Missing Energy Decay (Bàτν) in Data

The clean e+e- environment makes this possible
But we need to keep the beam-related backgrounds under control

20

Example: Belle Bàτν results with full reprocessed data sample andeither hadronic or semileptonic tags (PRD 92, 051102 (2015))
Hadronic tags:
63±22.5 (3σ)
Idea: With the “single B meson beam”,
we look for a single track from a τ,
missing energy/momentun and extra
calorimeter energy close to zero.

Semileptonic tags:
222±50 (3.8σ)With the full B factory
sta4s4cs only “evidence”.
No single observa4on fromeither Belle or BaBar.
èThe horizontal axis is the “Extra Calorimeter Energy”

21Complementarity of e+ e- factories and LHC(Slide adapted from A. Bevan)

The current combined Bàτυ limit places astronger constraint than direct searches
from LHC exps. for the next few years.
1 ab-1

Belle II

This region is allowed

rH =

✓

1

m2B
2
tan
m2H

◆2

Currently inclusive bàsγ rules out
mH+ below ~480 GeV/c2 range at
95% CL (independent of tanβ), M.
Misiak et al. (assuming no other NP)
hnp://arxiv.org/abs/1503.01789
22

A three-body taleSlide adapted from A. Soﬀer

23

Example from a BaBar paper
Signals in BàD(*) τν (489±63, 888±63)
Missing mass variable:
mmiss2 =pmiss2=(p[e+e-]-ptag-pD(*)-pl)2
Pl* = momentum of lepton in B rest frame
But wait !!! Now possible at LHCb.
Produc3on of B meson pairs at thresholdis cri3cal to the separa3on of
backgrounds from the missing energy/
momentum signal.
24

BaBar collabora4on, Phys. Rev. Len. 109, 101802 (2012)“However, the combina4on of R(D)and R(D*) excludes the type II 2HDM
charged Higgs boson with a 99.8%
conﬁdence level for any value oftan(β)/mH+”

In other words, found NP but killed the 2HDM NP model.

25Apres Nagoya: World Averages for R(D) and R(D*)
July 23, 2015

Now 3.9σ from SM

It is obvious that we need two orders of magnitude of data to solvethese issues related to the charged Higgs.
26

One more Belle update, March 2016 (Moriond)
Talk by P. Goldenzweig(Karlsruhe)

Uses semileptonic tagging

April 2016:
The WA is now
4.0σ from the SM
arXIv: 1603.06711

27

Last Belle update, March 2016

hnp://arxiv.org/abs/1603.06711

Try to dis4nguish
SM and charged
Higgs in kinema4c
distribu4ons.

Both ﬁt well.

Can also constrain other types of NP couplings (e.g.
leptoquarks) , but need much more data28

Simple message from theworld’s flavor physicists:

Credit: Djouadi

WE NEED MOREDATA !!!

With apologies to Herodotus, Thucydides, Sparta, Persia…

Initial Belle II projections for charged Higgs sensitivity
Itoh,
Sato

29

Red Hot Flavor Physics

The stakes are getting higher

High Energy Physics History: finding
NP in AFB (using interference)

Conclusion: There is a Z boson at higher energy
even though colliders of the time did not haveenough s to produce it

AFB(BàK*l+l-)(q2)
The SM forward-backward
asymmetry in bàs l+ l- arises
from the interference between γ
and Z0 contributions.

ForwardBl+

Backward

lθ

l+

B
K*

l-

θ

K*

Ali, Mannel, Morozumi, PLB273, 505 (1991)

Note that all the heavy particles of the SM (W, Z, top) enter inthis decay.

More on AFB(BàK*l+l-)(q2)

Can in eﬀectvary √s for NP

AFB depends on q2= M2(l+l-)

Ali, Mannel, Morozumi, PLB273, 505 (1991)

The “zero-crossing” of AFB depends only on aratio of form factors and is a clean observable.

BàK* l l angular variables(skip today)
K* and l+ l- helicity
anglesAngle φ between
the normals to thetwo decay planes.

N.B. Recent LHCb
measurements include
φ angle data
From hnp://xxx.lanl.gov/pdf/
1606.00916v1

BàK*l+l-(q2) bootcamp (for reference)
Angular dependenced 3 (Γ ± Γ)!"=2d(Γ + Γ) / dqdΩ1(-) means theterm is only in Γ −Γ

Thanks to Rahul Sinha

FL is the longitudinalpolariza4on frac4on.

⎡3
⎤
2
2
⎢ 4 (1− FL )sin ϑ K + FL cos ϑ K⎥⎢⎥⎢ + 1 (1− F )sin 2 ϑ cos 2ϑ
⎥
L
K
L
⎢ 4
⎥
9 ⎢
⎥
2
2
2
−
F
cos
ϑ
cos
2
ϑ
+
S
sin
ϑ
sin
ϑ
cos
2
φ
K
L
3
K
L
⎥
32π ⎢ L⎢ +S sin 2ϑ sin 2ϑ cos φ + S (− ) sin 2ϑ sin ϑ cos φ ⎥
K
L
5
K
L
⎢ 4
⎥
(− )
2
⎢ + AFB sin ϑ K cos ϑ L + S7 sin 2ϑ K sin ϑ L sin φ⎥⎢ (− )⎥(− )2
2⎢⎣ +S8 sin 2ϑ K sin 2ϑ L sin φ + S9 sin ϑ K sin ϑ L sin 2φ ⎥⎦Introduce P4,5’= S4,5/sqrt[FL (1-FL)] toreduce/eliminate dependence on form factors

LHCb 3fb-1 results on BàK* µ+µ- (q2)Angular Asymmetries based on 2398±57 signal events“The P5’ measurements are only compatible with the SM
prediction at a level of 3.7σ…..A mild tension can also beseen in the AFB distribution, where the measurements are
systematically <=1σ below the SM prediction in the
Blank regions are the J/ψ and ψ’region 1.1<q2< 6.0 GeV2”
vetos

Theory from hnp://arxiv.org/abs/1510.04329

R. Aaij et al., JHEP 1602, 104 (2016)

Recent LHCb results on BàK* µ+µ- (q2)
Is HEP History repeating itself ? [But be sure this is
not a tricky SM form factor effect.]Why does NP appear first in this mode(and not others) ?

Possible answer: All the heavy particles of the SM (t, W, Z)
and maybe NP (except the Higgs) appear here. Sensitive to NP
via interference (linear effects and many types of couplings).

NP could mean “newpar4cles” (bump in some mass
spectrum at the LHC) or “newcouplings” (ﬂavor physics)
We would be happy to break the Standard Model.
Places where we might ﬁnd New
couplings

Right-handed currents:1- γ5è1+ γ5

A recent example of NP Fits to Bàs l l data
L. Hofer et al.,Moriond March
2016

Why
shouldI care ?

Fits use LCSR at
low q2 and la‹ceform factors at
high q2 and alldata on bàs l l

These plots mean there are NP
coupling(s) in the weak interaction

39

Theory issues on BàK* µ+µ- (q2)èCheck dependence on light-cone form factors (some checks
already done by Lattice QCD groups)
Major concernèCan tails of large BàK* [c-cbar]
or non-factorizable eﬀects produce
the anomalies found in the angular
distribu4ons ? (If all non-perturba4ve

eﬀects ﬂoat with arbitrary normaliza4on in
the ﬁt then the data can explained,
hnp://lanl.arxiv.org/abs/1512.07157)

à Use data near q2 =q2max (K* at rest), where symmetry

works (Heavy Quark Effective Theory) and constrains ratioof polarizations (no hadronic corrections)èStill find NP
40

Fit LHCb angular data at q2max (HQET limit)★ is the SM

SM

Contours at
1,3,5σData with 1σ, 5σ
uncertain4es

5σ signal for NP, requires
right-handed currents
A. Karan et al. (arXiv:
1603.04355) [R.Sinha group]

S4ll conﬁrma4on and more data isneeded to close the case for NP
41

(Skip today)~301 bàs l+lsignal eventsin Belle data
samplePaths to the future:
AFB(q2) for Inclusive bàs l+ lNo form factors
Precise result usefulfor NP diagnosis but
Belle II only (seehnp://arxiv.org/abs/
1503.04849)

hnp://arxiv.org/abs/1402.7134
To appear in PRD.

How can we establish NP in BàK* l-l+ ?
Ans: Observe and measure the rate for B → sννand thus isolate the Z’ penguin (C9) at Belle II

Ans: Verify hint of lepton universality
breakdown at Belle II (good electron eﬀ)

R. Aaij et al. (LHCb collab); PRL 113, 151601 (2014)

AnswerfromBuras etal.

According tohnp://xxx.lanl.gov/abs/
1605.07633, no signiﬁcant
SM radia4ve correc4ons

“We need more data !!”Apologies to Director Akira Kurosawa

To ﬁnd out whether there are NP couplings in the weak interac3on
P5’
Signal of~187 events

Belle I data S. Wehle,
DESY, arXiv: 1604.04042

(forreference)SuperKEKB Luminosity ProﬁleBelle/KEKB recorded ~1000 •-1 . Now change
units on y-axis to ab-1

N.B. To realize this steep turn-on, requires close coopera4on between BelleII and SuperKEKB [and interna3onal collabora3on on the accelerator].
This plot assumes a full and stable opera4on funding proﬁle.

Physics Reach of Belle II and the LHCb upgrade
Compe33on andcomplementarity

Gelato ﬂavors in Asakusa

Tofu Gelato ?

46

BàφKS

BàψKS
Tight race

Belle II
ahead

Belle IIdominates here

Tight race
Bàπ+ π- CPV

Bàη’KSBelle II Detector
BEAST (Backgroundcommissioning detector)

KL and muon detector:

Resis4ve Plate Counter (barrel outer layers)
Scin4llator + WLSF + MPPC (end-caps , inner 2barrel layers)

EM Calorimeter:CsI(Tl), waveform sampling (barrel)
Pure CsI + waveform sampling (end-caps)

Par4cle Iden4ﬁca4onelectrons (7GeV)Time-of-Propaga4on counter (barrel)
Prox. focusing Aerogel RICH (fwd)

Beryllium beam pipe
2cm diameter

Vertex Detector

2 layers DEPFET + 4 layers DSSD

positrons (4GeV)
Central Dri• ChamberHe(50%):C2H6(50%), small cells, long leverarm, fast electronics
48

Outer Detector

CsI(Tl) crystals wereretained. Improved
waveform sampling
readout.

Scintillator based endcap KLM was installed as well as twoscintillator-based layers in the barrel KLM. Barrel RPC(resistive plate chambers) were retained. Readout is new.

Barrel Par4cle Iden4ﬁca4on
A GEANT4 event display of a 2 GeV pion and kaon interac4ng in a
TOP [4me of propaga4on] quartz bar. (Japan, US, Slovenia, Italy)
Incoming
track

Vertexing/Inner Tracking
Beampipe
r= 10 mm
DEPFET pixels (Germany, Czech Republic, Spain…)
Layer 1 r=14 mm
Layer 2 r= 22 mm
DSSD (double sided silicon detectors) FWD/BWD
Layer 3 r=38 mm (Australia) Italy
Layer 4 r=80 mm (India)
Layer 5 r=115 mm (Austria)
Layer 6 r=140 mm (Japan)+Poland (so•ware), Korea

50

Belle II at Tsukuba Hall

May 2016:TOP in Belle II structureFirst TOP module arriving at Tsukuba Hall

Update: May 20, 2016 all 16 TOP
modules were installed into the Belle II
structure. Magne4c ﬁeld mapping then
CDC installa4on in 2nd half of August.

CDC (Central Dri• Chamber)
51

Reduce the mul4ple scanering
lever arm; reduce X0 (to preserve
intrinsic resolu4on)

In e+ e- scanering at 10-11
GeV, a cri3cal issue forvertexing is mul4ple
scanering.
Belle: r(beampipe) 2 cmà1.5 cm
Belle II: r(beampipe) 1cm
Improved resolu4on and nano-beams will
open new possibili4es for vertex analysis

Ks track
γ

π+ π-

γ

B vertex
IP profileγ

B decay point reconstruction
from the KS vertex, used in searches
for NP right handed currents.

Larger radial
coverage of SVD
52

“Full sized” pixel detector module 0

75 μm
thick

Pixel detector group from many ins4tutes anduniversi4es in Germany, also Czech Republicand Spain.

53

April 2016: Belle II VXD beam test at DESY
(DESY provides the infrastructure and facili4es forthis cri4cal beam test)

Incident DESY (2-6 GeV) e- test beam54

April 2016: Two full-sized Belle II DEPFET pixel detector
modules at DESY (readout full system with beam)
Working examples of L3, L4, L5, L6 SVD ladders

Test full-sized PXD modules in abeam. [Measure efficiency and S/
N].

Test the integrated PXD-SVD system.
This includes ROI (region of interest)
extrapolation from the SVD tracker tothe PXD, which is needed to reduce the55large data volume.

For reference: PXD schedule and milestones

56

Belle II at IPMU in 柏の葉, Japan

Construc4ng two layers of the Belle II SVD detector in theclean room on the 1st ﬂoor. Dr T. Higuchi is the L6 leader.

Produc4on on
both layers
has started.

Japan (Layer 6) and India/Tata Ins4tute (Layer 4)L4 mechanical prototype57

For reference: Ladder produc4on schedule
End of FW/BW
produc4on:
Jul 2016

End of L6
produc4on:
Sep. 2017

To be updated next week at the
Belle II general mee3ng

58For reference: Integra4on schedule

SVD ready: Dec 2017
Start of laddermount:
Feb 2017

VXD integra4on:
from Dec 2017

To be updated next week at the
Belle II general mee3ng

59

SVD ladder produc4on status• Pisa (FW/BW) 85% (66%) of the backward (forward)
sub-assemblies completed as of Jun 6, 2016
• Melbourne ( L3 ) start of class A produc4on delayed by
L3 bridge reproduc4on delays, bond machine troubles
and L3 cooling studies – to start a•er the June B2GM
• TIFR ( L4 ) one class A ladder completed (out of 10),assembly of second one started on June 13, 2016
• HEPHY ( L5 ) third class A ladder (out of 12) to becompleted on June 17, 2016
• Kavli IPMU ( L6 ) ﬁrst class A ladder (out of 16) will becompleted on June 15, 2016
C. Schwanda, T. Higuchi et al

Executive Summary of
Detector Construction Status• Outer detector: EKLM, BKLM, TOP are installed; CDC in
August; readout and DAQ integra4on is a lingering
concern. Delay in endcap ARICH schedule (HV hardware
and sparking of HAPDs) may impact Phase II startup
schedule. Roll-in of outer detector by Christmas.
• Inner detector: SVD produc3on has started; sometechnical surprises; concerns about L6 schedule andmanpower; PXD produc3on is gearing up. Problems with
SVD-PXD readout/DAQ integra4on revealed by April
2016 DESY beam test. Tests of CO2 cooling and RVC(Remote Vacuum Connec4on) on track in Germany but
need to be integrated at Tsukuba Hall in 2017.
• Overall, Belle II construc3on and integra3on are on-track
but the schedule is 3ght. The Belle II collabora4on is fully
mobilized and performed well for the outer detector.
61

Some Belle II jargon

BEAST PHASE I: Simple background commissioning
detector (diodes, diamonds TPCs, crystals…). No ﬁnal
focus. Only single beam background studies possible[started in Feb 2016].
See talk by H. Nakayama-san
for results and details.

BEAST PHASE II: More elaborate inner backgroundcommissioning detector. Full Belle II outerdetector. Full superconduc4ng ﬁnal focus. No
vertex detectors.

Belle II Schedule

HEP world: When do we start Belle II ?
BEAST PHASE I: Started in Feb
2016 (Belle II roll-in at the endof the year)
BEAST PHASE II: Starts in ~Nov
2017 [incl. ﬁrst collisions;limited physics without vertex
detectors]
Belle II Physics Running: Fall2018 [vertex detectors in]

QCSL at KEK, Dec 2015
63

Conclusions• Flavor physics is exci4ng and fundamental. Did wejust ﬁnd NP via new weak interac3on couplings ?
• Flavor could be the path for the future of HEP but weneed much more data.

• Time for a Paradigm Shif ?
SuperKEKB commissioning started in February. Belle II rolls in at theend of the year. First collisions in fall 2017. Belle II physics runs in2018 [and the LHCb upgrade in ~2021]. These facili3es will
inaugurate a new era of ﬂavor physics and the study of CP viola3on.
64

2015 ARC Recommenda4on

Strong interac4on physics

BaBar hasalready taken~30 •-1 here

Weak interac4on physics
B Bbarthreshold

N.B. broken horizontal scale
R. Mussa at
QWG 2016

hnps://indico.hep.pnnl.gov/event/0/session/24/contribu4on/
86/material/slides/1.pdf

65

Upsilon(5S)/(6S) energy region
Only 1-2 •-166

Issues for special Upsilon(nS) runs

67

A. E. Bondar, M. B. Voloshin
Phys. Rev. D 93, 094008 (2016)

Upsilon(6S) issues
R. Mizuk@B2TIP,
Krakow

68

Voloshin,
B2TIP Pinsburgh

Upsilon(6S) issues

✔

✔

69

Hunting for (b bbar g) “QCD hybrids”
Tetraquark (4-quark) states such as the Z(4430) first seen by Belle in 2003
Pentaquark (5-quark) states first observed by LHCb in 2015

Page, Swanson and Szczepaniak
Phys. Rev D. 59, 034016 (1999)
70

Review of Phase II recommenda4ons

Latest Proposal:Once collisions are established, record ~2 fb-1 at theUpsilon(4S); verify functionality of Belle II; check B
meson reconstruction.
Take remaining ~20 fb-1 at the peak of the Upsilon(6S)(build a unique dataset for strong interaction physics toprovide initial early Belle II physics publications.)71

Backup slides

72More backup material

S. Korpar, S. Nishida et al

S. Korpar, S. Nishida et al

S. Korpar, S. Nishida et al

Reminder: SVD ladder structure

SVD Classiﬁca4on scheme
Class A produc4on, useable forthe ﬁnal detector
Class B, electrically working but
some lower quality components
Class C
Mechanically accurate but notelectrically working

Slide from last two
B2GM’s !!

Belle II DAQCurrent major Belle II challenge is readout integra3onof outer detectors [s3ll a key issue at this B2GM]

Large numbers of
FPGAs on front-end;large number ofCPUs.

Complexity of
firmware andinterfaces isproblema4c.

78

“Missing Energy Decay” in a Belle II GEANT4 MC simula4on
Signal BàK ν ν
tag mode: BàDπ; DàKπView in r-z

Zoomed view of the vertex
region in r--phièBelle II Software is in a fairly advanced state (T. Kuhr
(LMU) is the Belle II software coordinator)

79

“Missing Energy Decay” in a Belle II GEANT4 MC simula4on
Bàτν, τàeνν

BàDπ, DàKπππeZoomed view ofthe vertex region80BEAST Phase I Highlight

SuperKEKB vacuum scrubbing to reduce
LER beam gas backgrounds in Belle II
LER integrated beam dose > 100 A-h

BEAST background in the LER vs 4me

BEAST data shows the LER backgrounds
decreasing as vacuum scrubbing proceeds.

SuperKEKB vacuum scrubbing to reduce
HER beam gas backgrounds in Belle II
BEAST background in the HER vs 4me

BEAST data shows the HER backgrounds
decreasing as vacuum scrubbing proceeds.

BEAST Phase I Highlight

April 2016: Large Touschek background observed in the LER

Bkg inBEAST

Ver4cal beam size from size monitor (not measured at IP)àWill need excellent collimators to handle nano-beambackgounds.

Innovative Technologies in Belle II
Pixelated photo-sensors play a central role
MCP-PMTs in the iTOP
HAPDs in the ARICH
SiPMs in the KLM, DEPFET pixels
Waveform sampling with precise 4ming is “saving our buns”.
Front-end custom ASICs (Applica4on Speciﬁc Integrated
Circuits) for all subsystems èa 21st century HEP experiment.
Pixel detector [3 custom German ASICs: DCD, DHP, Switcher]
KL/muon detector (TARGETX ASIC)
Electromagne4c calorimeter(New waveform sampling backend with good 4ming)
iTOP par4cle iden4ﬁca4on (IRSX ASIC)
Aerogel RICH (KEK custom ASIC)
Central Dri• Chamber (KEK custom ASIC)
SVD (APV2.5 readout chip adapted from CMS)

Highlights of Belle II construction
SuperKEKB hardware is being ﬁnalized.

BEAST PHASE I beampipe installed

S/N

Hits

Final Belle II SVD ladder in CERN
beam in June (working well !)(a) CDC arriving at Tsukuba Hall; (b) ﬁrst cosmics
with partly instrumented electronics (6 layers)Rare B Decays
Two event displays

J. Albrecht

Goa, India

86

LHC found the rarest B decay; Bsàμ+ μ-

BF ~O( 10-9)

N. B. Here and in bàs l+ l- all the heavy par4cles of the
SM enter as virtual par4cles in the Feynman diagrams

87

LHCb

Skip today

CMS

88

Tau Lepton Flavor Viola4on
Example of the decay
topology

Belle II will push many limits below
10-9 ; LHCb has very limited
capabili4es.

89Mixing and CP violation in the D system
However, the x signal is marginal

There is a verystrong y signal

D mixing: Another new physics phase !
ϕ~2ηA2λ5λ~ O(10 −3 )CPV in interf. mix./decay:

CPV in D system negligible in SM

q Af
AM iϕ
Im
≡ (1 +)e ≠ 0; ϕ ≠ 0
p Af
2

The existence of D mixing (if x is
non-zero) allows us to look for
another poorly constrained new
physics phase but this time fromup-type quarks.
(c.f. CPV in Bs mixing)
0, 50 ab-1 go below 20
Current WA sensitivity ~±2091CPV in the charged lepton sector• There is mixing in the neutrino (neutral
lepton) sector. CP viola4on is possible too.
BaBar rate anomaly ??

Can we explore at Belle II ?

M. Bischo•erger et al, Phys. Rev. Len. 107, 131801 (2011)

Beast Phase II & New Triggers• Update to First-physics report:
BELLE2-NOTE-PH-2015-003 Y(2S),
Y(3S), Y(6S), Scan proposals

C. Hearty• Beast Phase II Physics Task Force formed
to study physics with this configuration (B.
Fulsom).
• Belle Y(1S) decay data used for Pythia 8
MC tuning in Belle II (U. Tamponi).

•

HLT & L1 Trigger Menu underdesign. Evolving
Trigger Menu (Link).

C-H. Li

Discussed in Nakada-san’s talk94

LHCb Upgrade: Key Feature is Trigger-less readout95

B factories: Check CP violation in bàc [ubar d] processes

2015: First joint BaBar-Belle data analysis M. Rohrken et al“Color-suppressed” BàD hwhere D0 is a CP eigenstate and h0=π0, η, ω

Combining Belle and BaBar datasets,~1260 signal events, obtain a 5.4σ CPviola4on signalèFirst observa4onsin(2βeﬀ)=0.66±0.10(stat)±0.06(sys)
Phase of
Vtd again

Conclusion: CP violation in bàc ubar d modes is
the same as in bàc cbar s modes (e.g. BàJ/ψ KS)

96

More backup

97

Belle II iTOP at Fuji Hall/Hawaii

Module 01 assembly at Fuji Hall

Module 04 assembly at Fuji Hall

Produc4on tes4ng of readout with single
photo-electron laser pulses in Hawaii;
electronics resolu4on ~35ps
All quartz and electronics in hand; now
tes4ng and assembling.
98

DESY contribu4ons to SuperKEKB
An important piece of SuperKEKB

Also SuperKEKB beam backgroundsimula4on: Synchrotron Radia4on (SR)99

Major DESY contributions to Belle II
Thermal mockup of the vertex detectors/CO2 cooling(many ini4al results, on-going)

Precise mapping of the 1.5 T
B field of the Belle IIsuperconducting solenoid(starts June 2016)

Software Alignment of Belle II detectors(standard Belle II package)

GRID computing and Collaborative Computing Services
for Belle II (starts summer 2016)
Not a complete list !

100