An introduction of particle physics in China

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An introduction of particle physics in China
IHEP

• Yifang Wang
• Institute of High Energy Physics
• Sep. 2, 2008, Erice

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Chinese philosophers likes particle physics

• ????,????,???? ---- ?? Break a ruler by
  half every day, never finish even after ten
  thousands generations ----- Zhuangzi
  350 B.C.
• ?????????? ----- ??? 1964
• Matter may be break up infinitely ---- Mao
  Zedong 1964

Reasonable support to particle physics in the
last ten years
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Institute of High Energy Physics

• Comprehensive and largest fundamental research
  center in China
• For
• Particle physics
• Astroparticle physics
• Theoretical physics
• Accelerator technologies and applications
• Synchrotron radiation
• 1000 employees, 650 physicists and engineers

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Particle physics in China

• Before 1949 Educational
• 50-60s Dubna
• 70s Cosmic-rays
• 80-90s BEPC, LEP

Now
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Experimental particle physics in China

• Large international collaboration
• LHCATLAS, CMS
• KEKB BELLE
• AMS, KamLAND, SuperK,
• RHIC Star,
• ILC
• Domestically based high energy physics
  experiments
• BEPC BEPCII BESII/BESIII
• Daya Bay reactor neutrino experiment
• Yang-Ba-Jing cosmic-ray observatory
• Hard X-ray modulated telescopy

A balance of physics opportunities, financial
resources, technological capabilities and needs,
man power, experience,
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Beijing ee- collider(BEPC) consists of Linac,
Storage Ring, Spectrometer(BES) and Synchrotron
Radiation Facility(BSRF)It started construction
in 1984 and completed in 1988
Ecm2-5 GeV, L 5?? 1030 /cm2?s _at_ J/y peak
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BESII data samples
A typical event in BES detector ?(2S)?J/?pp-
J/?? ee-
BESII
150 papers on PRL, PRD, PLB
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R value and ? excited states
From PDG
Significantly improved data quality in 2.0-5.0
GeV region,
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An enhancement near the ppbar threshold
Observation of X(1835)
J/y?gpp
7.7?
0
0.2
M(pp)-2mp (GeV/c2)

• Phys. Rev. Lett., 91 (2003) 022001

Phys. Rev. Lett. Dec.31, 2005
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Observation of ?? threshold enhancement in J/? ?
???
Phys. Rev. Lett. 96, 162002 (2006)   
DOZI process
Phase Space
Side-band
JPC 0
M

• 105?20?28 MeV
• BR (2.61?0.27?0.65)x10-4

relation with f0(1710),f0(1790)
? multiquark/hybrid/glueball ?
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New observation of a broad resonance in J/? ?
KK- ?0
Background

• X pole position

PWA analysis and parity conservation
considerations yield
Too many 1--, Width is much broader than other
mesons multiquark state ?
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Observation of ????-J/?

• Nobs 17.84.8
• Nbkg 6.01.4
• Nsignal11.85.0
• BR(0.340.140.09)
• ?(803323) keV
• First non-DDbar decay of ?
• Agree with multipole expansion
• Kuang PRD65, 094024 (2002)
• Confirmed by CLEOc later
• BR(0.1890.0200.020) PRL96, 082004 (2006)

Blank ee- Shaded ??-
PLB605, 63 (2005)
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The future of BEPC

• In early 80s, the decision to build BEPC was a
  great success
• Rich physics opportunities with limited
  investment
• A total of 150 papers published in PRL, PRD,
  PLB,
• A total of 300 records in particle data book
• Several highlights well known in the community
• Established the foundation of particle physics
  and its related technology in China accelerator,
  detector, electronics,
• Started the era of synchrotron radiation
  application in China
• Technology transfer
• In early 90s, the community started the
  discussion for the future. The conclusion was to
  continue the tau-charm physics study by a major
  upgrade of the accelerator and detector (BEPCII /
  BESIII)
• The physics window is precision charm physics and
  search for new physics
• High statistics high luminosity machine high
  quality detector
• Small systematic error high quality detector

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Unique physics opportunities

• In a regime of transition between pQCD and
  non-pQCD
• Can provide calibrations and tests of LQCD
• Rich spectra of light hadrons for Quark model
  test and for searches of new hadrons
• Rich gluonic matter production for QCD test
• Near the production threshold of tau-charm good
  for quantum correlation constraints
• Complementary to LHC experiments

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BEPC II Storage ring Large angle, double-ring
RF
RF
SR
Beam energy 1-2 GeV Luminosity
11033 cm-2s-1 Optimum energy 1.89
GeV Energy spread 5.16 10-4 No. of
bunches 93 Bunch length 1.5 cm Total
current 0.91 A SR mode 0.25A _at_ 2.5
GeV
IP
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Installation of linac is complete
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Test results of LINAC
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Two storage rings in the BEPC tunnel
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Storage ring commissioning Oct. 25, 2007
accumulation of electron beams Oct. 31, 2007
accumulation of positron beams Nov. 18, 2007
first ee- collision Mar. 2008 Collision 500 mA
500 mA, Luminosity 1
1032 cm-2s-1
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The BESIII Detector
SC magnet, 1T
Magnet yoke
RPC
TOF, 90ps
Be beam pipe
MDC, 120 mm

CsI(Tl) calorimeter, 2.5 _at_1 GeV
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Drift chamber

• To measure the momentum of charged particles by
  its bended curvature in a magnetic field
• Design spec. Single wire reso.
  dE/dx reso.
• CLEO
  110mm, 5.7
• Babar
  110mm, 6.2
• Belle
  130mm, 5.7
• BESIII
  120mm 5-6
• Rin 63mm Rout 810mm length 2400 mm
• 7000 Signal wires 25(3 Rhenium) mm gold-plated
  tungsten
• 22000 Field wires 110 mm Al
• Gas He C3H8 (60/40)
• Momentum resolution_at_1GeV

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BESIII CsI(Tl) crystal calorimeter

• To measure the energy of electromagnetic
  particles
• Barrel 5280 crystals,Endcap 960 crystals
• Crystal (5.2x 5.2 6.4 x 6.4) x 28cm3
• Readout 13000 Photodiodes, 1cm?2cm,
• Energy range20MeV 2 GeV
• position resolution 6 mm_at_1GeV
• Tiled angle theta 1-3o, phi 1.5o

Babar 2.67 _at_1GeV BELLE 2.2 _at_1GeV CLEO
2.2 _at_1GeV BESIII 2.5_at_1GeV
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Crystals hanged from rear face, no partition walls
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m system RPC

• 9 layer, 2000 m2
• Special bakelite plate w/o lineseed oil
• 4cm strips, 10000 channels
• Noise less than 0.1 Hz/cm2

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Super-conducting magnet 1T_at_3400 A
Thermal insulation
assembly
wiring
installation
transportation
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Field mapping Dr lt 0.5 mm, DB lt 0.1
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MDC and TOF installation clearance lt 10 mm
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EMC installationclearance lt 15 mm
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Celebrate successful installation
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First cosmic-ray event

• triggerDAQdetector(MDCEMCTOFMUON)
• Trigger conditioncosmic-rays

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Testing results of cosmic-rays

• MDC single wire resolution
• lt design spec. ?110
• EMC energy resolution
• lt design spec. ?140
• TOF time resolution
• lt design spec. ?130
• MUC efficiency
• lt design spec. ?100

Ready for the first physics results
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First collision event on July 19, 2008
Up to now, 1 M y events collected
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Physics at BEPCII/BESIII

• Precision measurement of CKM matrix elements
• Precision test of Standard Model
• QCD and hadron production
• Light hadron spectroscopy
• Charmonium physics
• Search for new physics/new particles

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Light hadron spectroscopy

• Baryon spectroscopy
• Charmonium spectroscopy
• Glueball searches
• Search for non-qqbar states

1010 J/y events is probably enough to pin down
most of problems of light hadron spectroscopy
Spectrum of glueballs from LQCD
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Confirm X(1835) at BESIII ( 58M J/? )
One week at BESIII
2 years at BESII
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Confirm ppbar threshold enhancement
at BESIII ( 58M J/? )
2 weeks data taking at BESIII
2 years data taking at BESII
1010 J/y events is revolutionary for the light
hadron spectroscopy
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Precision measurement of CKM---- Branching
rations of charm mesons

• Vcd /Vcs Leptonic and semi-leptonic decays
• Vcb Hadronic decays
• Vtd /Vts fD and fDs from Leptonic decays
• Vub Form factors of semi-leptonic
  decays
• Unitarity Test of CKM matrix

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Precision test of SM and Search for new Physics

• DDbar mixing
• DDbar mixing in SM 10 3 - 10 10
• DDbar mixing sensitive to new physics
• Our sensitivity 10-4
• Lepton universality
• CP violation
• Rare decays
• FCNC, Lepton no. violation, ...

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BESIII collaboration
Europe (4) GSI, Germany University of Bochum,
Germany University of Giessen, Germany JINR,
Dubna, Russia
China (23) IHEP, CCAST, Univ. of Sci. and Tech.
of China Shandong Univ., Zhejiang Univ. Huazhong
Normal Univ., Wuhan Univ. Zhengzhou Univ., Henan
Normal Univ. Peking Univ., Tsinghua Univ.
, Zhongshan Univ.,Nankai Univ. Shanxi Univ.,
Sichuan Univ Hunan Univ., Liaoning Univ. Nanjing
Univ., Nanjing Normal Univ. Guangxi Normal Univ.,
Guangxi Univ. Hong Univ., Hong Kong Chinese Univ.
USA (7) Univ. of Hawaii, Univ. of
Washington,Univ. of Minisolta, Carnegie Mellon
Univ., RPI, Rochester Uni., Florida Univ.
Japan (1) Tokyo University
We expect great physics results from BESIII
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Daya bay reactor neutrino oscillation experiment

• Reference hep-ex/0610024
• hep-ex/0701029

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Neutrino oscillation PMNS matrix
If Mass eigenstates ? Weak eigenstates ? Neutrino
oscillation Oscillation probability
P(n1-gtn2) ? sin2(1.27Dm2L/E)
Atmospheric
solar
bb decays
crossingCP ?q13
EXO Genius CUORE NEMO
Homestake Gallex SNO KamLAND
Super-K K2K Minos T2K
Daya Bay Double Chooz NOVA
A total of 6 parameters 2 Dm2, 3 angles, 1 phases
2 Majorana phases
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Why at reactors

• Clean signal, no cross talk with d and matter
  effects
• Relatively cheap compare to accelerator based
  experiments
• Can be very quick
• Provides the direction to the future of neutrino
  physics
• Reactor experiments
• Pee ? 1 ? sin22q13sin2 (1.27Dm213L/E) ?
  
• cos4q13sin22q12sin2
  (1.27Dm212L/E)
• Long baseline accelerator experiments
• Pme sin2q23sin22q13sin2(1.27Dm223L/E)
• cos2q23sin22q12sin2(1.27Dm212L/E)
  ?
• A(r)?cos2q13sinq13?sin(d)

Small-amplitude oscillation due to ?13
Large-amplitude oscillation due to ?12
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Current Knowledge of ?13
Global fit fogli etal., hep-ph/0506083
Direct search PRD 62, 072002
Sin2(2?13) lt 0.18
Sin2(2?13) lt 0.09
Allowed region
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• No good reason(symmetry) for sin22q13 0
• Even if sin22q13 0 at tree level, sin22q13 will
  not vanish at low energies with radiative
  corrections
• Theoretical models predict sin22q13 0.1-10

model prediction of sin22q13
Experimentally allowed at 3s level
An experiment with a precision for sin22q13
less than 1_at_90 CL is desired
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How Neutrinos are produced in reactors ?

The most likely fission products have a total of
98 protons and 136 neutrons, hence on average
there are 6 n which will decay to 6p, producing
6 neutrinos
Neutrino flux of a commercial reactor with 3
GWthermal 6? 1020 /s
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neutrino detection Inverse-ß reaction in
liquid scintillator
t ? 180 or 28 ms(0.1 Gd)
n p ? d g (2.2 MeV) n Gd ? Gd g
(8 MeV)
Neutrino Event coincidence in time, space and
energy
Neutrino energy
10-40 keV
1.8 MeV Threshold
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Reactor Experiment comparing observed/expected
neutrinos
Typical precision 3-6

• Precision of past exp.
• Reactor power 1
• Spectrum 0.3
• Fission rate 2
• Backgrounds 1-3
• Target mass 1-2
• Efficiency 2-3

We need a precision of 0.4
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xperi
Proposed Reactor Neutrino Experiments
Krasnoyasrk, Russia
Chooz, France
Braidwood, USA
Kashiwazaki,Japan
Young Gwang, South Korea
Diablo Canyon, USA
Daya Bay, China
Angra, Brazil
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Daya Bay nuclear power plant

• 4 reactor cores, 11.6 GW
• 2 more cores in 2011, 5.8 GW
• Mountains near by, easy to construct a lab with
  enough overburden to shield cosmic-ray
  backgrounds

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Layout

• Near-far cancellation
• Two near sites and one far sites connected by
  3000 tunnel
• Event rate
• 1200/day near
• 350/day far
• backgrounds
• B/S 0.4 near
• B/S 0.2 far

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Detector design multiple neutrino detector
modules and multiple muon veto

• Multiple detector modules to reuce errors and
  cross check
• Multiple muon veto
• Two-layers of cerenkov detector
• RPC at the top
• Total efficiency gt (99.5 ? 0.25)

Redundancy is a key for the success of this
experiment
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Central Detector modules

• Three zones modular structure
• I. target Gd-loaded scintillator(R. Hahns
  talk)
• II. g-catcher normal scintillator
• III. Buffer shielding oil
• 192 8PMT/module
• Reflector at top and bottom
• Photocathode coverage
• 5.6 ? 12(with reflector)

20 t Gd-LS
LS
oil
sE/E 12/?E
sr 13 cm
Target 20 t, 1.6m g-catcher 20t, 45cm Buffer
40t, 45cm
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Prototype

• Motivation
• Validate the design principle
• Test technical details of tanks
• Test Gd-LS
• Test calibration and Pu-C source
• Achievements
• Energy response MC Comparison
• Reconstruction algorithm
• Neutron response Pu-C source
• Effects of reflectors
• Gd-LS

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Sensitivity to Sin22q13

Other physics capabilities Supernova watch,
Sterile neutrinos,
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Civil construction

• Tunnel length 3100m
• three experimental halls
• One assembly hall
• Water purification hall

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Schedule

• begin civil construction Oct. 2007
• Bring up the first pair of detectors Dec. 2009
• Begin data taking with the Near-Far
• configuration Dec. 2010

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Daya Bay collaboration
Europe (3) JINR, Dubna, Russia Kurchatov
Institute, Russia Charles University, Czech
Republic
North America (14) BNL, Caltech, George Mason
Univ., LBNL, Iowa state Univ. Illinois Inst.
Tech., Princeton, RPI, UC-Berkeley, UCLA, Univ.
of Houston, Univ. of Wisconsin, Virginia Tech.,
Univ. of Illinois-Urbana-Champaign,
Asia (15) IHEP, Beijing Normal Univ., Chengdu
Univ. of Sci. and Tech., CGNPG, CIAE, Dongguan
Polytech. Univ., Nanjing Univ.,Nankai Univ.,
Shenzhen Univ., Tsinghua Univ., USTC, Zhongshan
Univ., Hong Kong Univ. Chinese Hong Kong Univ.,
Taiwan Univ., Chiao Tung Univ., National United
Univ.
200 collaborators
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AS?,ARGO Allsky, High Duty Cycle
3TeV
300GeV
Sino-Italian ARGO experiment (RPC hall)
Sino-Japanese AS ? experiment (scintillation
detector array)
Sino-Italian ARGO experiment (part of RPC carpet)
AS? scintillation detector
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Chinese Spallation Neutron source
Phase I 100 kW, upgradeable up to 500 kW

• To be built by IHEP in Dongguan, south of
  China, near Hong Kong

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HEP planning in China
BESII physics
BESIII physics
BESIII construction
Future ?
ATLAS CMS physics
ATLAS CMS construction
ILC
Daya Bay construction
Daya Bay physics
reactor experiment ?
ASg
ARGO
ASg ARGO physics
A major upgrade ?
HXMT
HXMT physics
Space or south pole
2005
2015
2010
Theory, detector and electronics,