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High Intensity Electron Positron Accelerator Facility

(HIEPAF)Zhengguo Zhao

On behalf of Steering Committee

Collaborative Innovation Center for Particle Physics and Interaction University of Science and Technology of China

Institute of High Energy Physics, CASInstitute of Theoretical Physics, CAS Tsinghua UniversityUniversity of Chinese Academy of Sciences Shangdong University Shanghai Jiaotong UniversityPeking UniversityNanjing University Nankai UniversityWuhan University Hua Zhong Normal University

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Outline

• What project are we proposing ?• What is HIEPAF? • Why do we propose HIEPAF? • Current status

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What Project Are We Proposing?

High Intensity Electron Positron Accelerator Facility (HIEPAF)

• Providing peak luminosity about 1x1035 cm-2s-1 at 4 GeV for physics at tau charm sector, covering Ecm = 2-7 GeV.

• Being a 3rd/4th generation SRF (synchrotron radiation facility).

• Reserving the potential for FEL( free electron laser) study with the long LINAC.

Possible Schematic Layout

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Features of the t-c Energy Region Rich of resonances, charmonium and charmed mesons. Threshold characteristics (pairs of , D, Ds, charmed baryons…). Transition between smooth and resonances, perturbative and

non-perturbative QCD. Mass location of the exotic hadrons, gluonic matter and hybrid.

5t+t- DsDs LcLc

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Physics at t-c Energy Region

_

• Precision DQED, am, charm quark mass extraction. • Hadron form factor(nucleon, , ).L p

R scan

R=s(

e+ e-

hadr

on)/

s(e

+ e-

m+ m

- )

• Hadron form factors• Y(2175) resonance• Mutltiquark states

with s quark, Zs• MLLA/LPHD and QCD

sum rule predictions

• Light hadron spectroscopy• Gluonic and exotic states• Process of LFV and CPV• Rare and forbidden decays• Physics with t lepton

• XYZ particles• Physics with D

mesons• fD and fDs

• D0-D0 mixing• Charm baryons

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Highlighted Physics Program

• Search for new forms of hadron and study their properties.

• The nucleon/hadron electromagnetic form factors (NEFFs) and QCD study in none perturbative region.

• Search for new physics beyond the SM.

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Key science question: Is there any new forms of hadron exist ?

• Exotic hadrons: made of quarks and possibly gluon, but do not have the same quark content as ordinary hadrons. They are not predicted by the simple quark model.

• After several decades’ effort, XYZ particles, such as X(3872), Y(4260) and Zc(3900) discovered by Belle, Babar and BESIII experiments.

• To reach conclusive evidence of an exotic hadron, an e+e- collider in the t-c sector, which is able to provide much higher statistical data and cover broader energy range is essential.

Standard hadrons Exotic hadrons

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Exotic Hadrons(possible combination of quark and glue)

Pentaquar

Hybrid

S=+1 Baryon Tightly bound diquark-diantiquark

Tightly bound 6-quark state

Loosely bound meson-antimeson

Color-single multi-glue bound state

qq glue hybrid_

Pentaquark H-diBaryon Tentraquark

Meson molecule Glueball

g

gg

XYZ Particles: Candidate of Exotic HadronsY(4660)Y(4630)

Y(4008)

BELLE: PRL99, 142002

BESIII: Primary

BESIII: PRL(2013) 252001

Zc+-(3900)p+-J/y

e+e- X(3872)

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Zc(3900) Observed at BESIIII and Belle

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• M = 3894.56.64.5 MeV• = 632426 MeV• 159 49 events• >5.2

• M = 3899.03.64.9 MeV• = 461020 MeV• 307 48 events• >8

BESIII at 4.260 GeV: PRL110, 2520010.525 fb-1 in one month running time

Belle with ISR: PRL110, 252002967 fb-1 in 10 years running time

重要科学媒体报道 Zc(3900)

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2013 年物理重要进展之首！

SLAC Inspire ： 101 次引用

Cristina Morales

Space-like:FF real

Time-like:FF complex

, Λ Λ

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Nucleon Electromagnetic Form Factors(NEFFs) Spatial distributions of electric charge and current inside the nucleon

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Nucleon Electromagnetic Form Factors (NEFFs)

• Key science question: why do quarks forms colourless hadrons with only two stable configurations, proton and neutron?

• NEFFs are among the most basic observables of the nucleon, and intimately related to its internal structure.

• Nucleons are the building blocks of almost all-ordinary matter in the universe. The challenge of understanding the nucleon's structure and dynamics has occupied a central place in particle physics.

• The fundamental understanding of the NEFFs and HEFF (hadron form factor) in terms of QCD is one of the outstanding problems in particle physics.

Cristina Morales16

The Measurement of Proton FF—Space-likeThere have been many measurements of the proton form factors in the space-like region. At Jlab, the proton factor ratio was measured precisely with an uncertainty of ~1%, based on which the proton electronic and magnetic radii could be extracted.

JLab

JLab

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Proton Form Factor: IGEI/IGMI

time-like

Complete picture of the nucleon structure requires space-like and time-like measurements!

10-24% precision from B factory

Only 2 measurements, but results are contradict

QCD predict

Babar: 469 fb-1 10-24% precisionBESIII: 0.4 fb-1 ~10% precision (expected)

first time extraction without any assumption.

δ|REM

|/|REM

| ~ 9% - 35%

δ|GM|/|G

M| ~ 3% - 9%

δ|GE|/|G

E| ~ 9% - 35%

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Measurement of Proton FFs with BESIII

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Measurement of Proton FFs at HIEPAFExample @ 2.23 GeV

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Nsig REM/REM / Luminosity (pb-1)

comment

614±24 24% 3.9% 2.631 BESIII test run3881±62 9.5% 1.6% 16.630 BESIII expected156253±395 1.5% 0.25% 669.533 HIEPAF reach 1389898±624 0.96% 0.16% 1670.69 HIEPAF reach 2

HIEPAF reach 1 HIEPAF reach 2

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New Physics• The discovery of the Higgs particle completes the list of the

particles in the SM. • Physics beyond the SM due to phenomena that cannot be

explained within the SM framework: - SM does not explain gravity - SM does not supply any fundamental particles that are good dark matter candidates, nor be able to explain dark energy - No mechanism in the SM sufficient to explain asymmetry of matter and anti-matter. • No evidence of new physics been found at high energy frontier,

it is important to search for new physics both directly and indirectly in the precision frontier.

Lepton Flavour Violating (LFV)

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CLFV processes sensitive to New Physics (NP)

through lepton-lepton coupling

m, t anomalous decays m e conversion

Anomalous magnetic moment

PSI Mu2e

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• The process e+e-+-, dominant background source at (4S), does

not contribute below 2E 4m/3 4.1 GeV.

• The favorable kinematical condition and the use of polarization can allow an UL(STCF in 1-2 years) ≤ UL(SuperBelle@Y in 12-15 yrs).

E

10.6 GeV

E

4.0 GeV

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MDC

PXD/SSD

PID-barrel PID-endcap

EMC

Superconducting magnet(0.7-1 T)

York/Muon

York/Muon

IP3~6 cm

10 cm15 cm

85 cm

105 cm

135 cm

185 cm

245 cm

120 cm

140 cm

190 cm

240 cm

300 cm

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Detector

MDC

• sxy=130 mm

• dE/dx<7%, sp/p =0.5% at 1 GeV

PXD• Material budget

~0.15%X0 / layer

• sxy=50 mm

PID• /K (and K/p) 3-4

separation up to 2GeV/c

EMC Energy range: 0.02-2GeVAt 1 GeV sE (%)

Barrel(Cs(I): 2 Endcap (Cs): 4

MUD• / suppression power

>10

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OrganizationHIEPAF

Physics&Software Detector

VertexTracker

EMCALPID

MUDSCM

Collectivity

Electronics

Trigger

DAQ

Theory

Generator simulation

CalibrationReconstruction

Infrastructure

Civilengineering

Technical supporting

Computing network

data service

SafetyEnvironment

Accelerator

Injector

Ring

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Activities

http://wcm.ustc.edu.cn/pub/CICPI2011/futureplans/

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HEPAF Study Time Line2013 2014 2015 2016 2017

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

Kick-offcollaboration forming

WorkshopsFeasibility study

Review

CDR, R&D TDR?

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Forthcoming Discoveries in Particle PhysicsTopic Crucial measurement Significance

WIMP Existence Dark Mater

Higgs boson M ~125 GeV Confirm spontaneous symmetry breaking in gauge theory

Super-symmetric particles Existence, M > 1 TeV Hope of understanding gravity

Technicolour particles Existence, M > TeV? Dynamic symmetry breaking, Composite Higgs

Gravitational waves (Gravitons)

Existence Support general relativity

Magnetic monopole Existence, mass, electric charge Electric and magnetic charge symmetry predicted by Dirac. Structure of gauge field

configuration

Free quarks Existence, fractional charge Would confuse all current prejudice

Neutrino mass and oscillation

M < 1 eV Structure of GUTs. Eventual fate of the universe

Exotic hadronGlueball

Mg = 1-2 GeV, Mexotic, c~4 GeVExistence

Understand QCD

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Summary

• HIEPAF is one of the possible options for high energy physics in China.

- Have interesting physics relating to key science questions - Have challenges in terms of key technologies - Reasonable scale and cost. - One stone, two birds. (STCF + SRF)

• Working groups are formed and are making progress with regular weekly meeting and workshops.

• Welcome to join the effort.

• Next workshop: June, Dec.

Produce >1000 different isotopes

1959, 678 m

1969

450 GeV

25 GeV

LEP: 1988-2000Ecm(e+e-) = 200-209 GeV

Discover W, Z

2007

LHC: Construction 1998-2007 Commission 2007 E(p+p) = 14 TeV

nt–n m

Over 50 years!

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Heavy Ion Accelerator Facility (HIAF)

(BR+SR+CR): high quality & intensity pulsed RIBs, b beam

high accuracy RIA, astrophysics, application… (BR+SR+CR): high power compressed U beam HED… (BR+SR+CR+ER): polarized e & p beams EIC

U+U, RIB+RIB… Merging Experiments…

10’s MW Spallation Target

Integrate with HIAF:

Power In Flight and

ISOL for RIB & b Beam

中科院：詹文龙Oct. 18. 2013

Could be an accelerator complex in China electron, proton, heavy ionNeutrino beam

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Extra Slides

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Data Sample at Resonances for 1 ab-1

BESIII 109 108 107 106 106 106

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Web Page

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Requirement To The Detector

Efficient event triggering, exclusive state reconstruction and tagging – high efficiency and resolutions for charged and neutral particles

• Best possible solid angle coverage• High resolution for charged particles: [0.05, 1.6] GeV• Good PID: [0.05, 2] GeV• Good e, g detection eff. and energy resolution: [0.02,2.5]

GeV • Good vertex detection: 50 mm

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Forthcoming Discoveries in Particle PhysicsTopic Crucial measurement Significance

WIMP Existence Dark Mater

GlueballExotic matter

M = 1-2 GeVExistence

Understand QCD

Higgs boson M ~125 GeV Confirm spontaneous symmetry breaking in gauge theory

Neutrino mass and oscillation

M < 1 eV Structure of GUTs. Eventual fate of the universe

Proton decay t > 4x1032 years Evidence for validity of GUTs

Magnetic monopole Existence, mass, electric charge Electric and magnetic charge symmetry predicted by Dirac. Structure of gauge field

configuration

Free quarks Existence, fractional charge Would confuse all current prejudice

Super-symmetric particles Existence, M > 1 TeV Hope of understanding gravity

Technicolour particles Existence, M > TeV? Dynamic symmetry breaking, Composite Higgs

Gravitational waves (Gravitons)

Existence Support general relativity

Beam Parameters

Beam energy (GeV)3.0

Revolution frequency (MHz) 0.302

Circumference (m) 992.8 Harmonic number 1656Coupling factor

0.005 βx, y @ IP (mm)1000,

1.0Emittance (nm.rad) 10 Beam-beam parameter 0.06Bunch length (mm) 10 Number of bunch 540

Momentum compaction 0.001 Bunch current (mA) 5.0SR energy loss/turn

(MeV) 0.716 Beam current (A) 2.7Synchrotron tune 0.0128 SR power (MW) 1.93RF voltage (MV) 2.0 Energy spread 8.12E-4

RF frequency (MHz) 500.06 Luminosity (cm-2s-1) 1.05E35

(Lattice and other related AP studies are under way)

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Precision EW

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Mike Roney, Dec 2012

See: https://agenda.infn.it/getFile.py/access?contribId=241&sessionId=64&resId=0&materialId=slides&confId=4442

Vus

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Emilie Passemar τ decays could provide a competitive measurement of Vus+ many other topics covered

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• The process e+e-+-, dominant background source at (4S), does

not contribute below 2E 4m/3 4.1 GeV.

• The favorable kinematical condition and the use of polarization can allow an UL(SuperB near threshold in 1-2 years) ≤ UL (SuperB@Y(4s) in 5-6 yrs). It will take 12-15 yrs to SuperBELLE).

E E E

10.6 GeV 4.25 GeV 4.0 GeV

Facilities for Particle Physics in China

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Cosmic RayObservatory

?

?

?

?

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• M = 388551 MeV• = 34124 MeV• 81 20 events 6.1

Confirmed with CLEOc data!

BESIII

Belle

CLEOc data at 4.17 GeV:

arXiv:1304.3036, PLB727, 366 (2013)

发现带电类粲偶素粒子Zc(3900)

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6 月 17 日，发现 Zc(3900) 的论文在《物理评论快报》发表，杂志编辑推荐，并特别

配发题为“新粒子暗示存在四夸克物质”的评论；《自然》杂志发表了题为“夸克

‘四重奏’开启物质世界新视野”的研究热点报道。

2013 年 3 月 26 日， BESIII 合作组宣布发现 Zc(3900) ； 3 月 30 日 Belle 合作

组提交 Zc(3900) 论文。因其衰变产生

和 J/ 介子，组成中含有粲夸克和反粲夸克

且带有和电子相同或相反的电荷，提示其

中至少含有四个夸克，可能是科学家长期

寻找的一种奇特强子。

BESIII: PRL110, 252002(2013)

BESIII Detector

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Muon counterResistive plate chamber Barrel: 9 layersEndcaps: 8 layerssspatial: 1.48 cm

Time-of-flight (TOF)Plastic scintillator sT(barrel): 105 pssT(endcap): 125 ps

Drift chamber (MDC)Small cell, 43 layerGas He/C3H8=40/60sxy=130 mm, dE/dx~6%sp/p = 0.6% at 1 GeV

ECAL calorimeter CsI(Tl): L=28 cm (15X0)Energy range: 0.02-2GeVAt 1 GeV sE (%) sl(mm)Barrel: 2.5 6.1Endcap: 5 9

1 T Super conducting magnet

Data acquisition Event rate: 4 kHzData size: 50 MB/s

Grid computingCPU: 3200 core Storage: 2.2 pB

RO channels: 104

Cost: 200 M RMB

5.1

m

5.6 m

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Discovery of X, Y and Z Particles

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• Fundamental properties of the nucleon– Connected to charge, magnetization distribution– Crucial testing ground for models of the nucleon

internal structure– Necessary input for experiments probing nuclear

structure, or trying to understand modification of nucleon structure in nuclear medium

• Driving renewed activity on theory side– Models trying to explain all four electromagnetic

form factors– Trying to explain data at both low and high Q2

– Progress in QCD based calculations

Nucleon Form Factors

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QCD predict

限于统计量，大多数实验假设 GE=GM:

B-factory 的测量精度在 10% ～ 24%.

只有两个实验组测量了 |GE/GM|, 但结果显然是不一致的。

质子形状因子测量：类时过程e+e-p:

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中子数据更稀缺，长期以来只有 Fenice 结果 (74 个 e+e- → 事例 , 0.4 pb-

1).

Assuming GE=0

现有数据表明中子的形状因子是质子的 2 倍，需要实验验证 !

中子电磁形状因子测量

意大利曾计划对 DANE/FINUDA 做重大专门改进来测量核子形状因子。提高中子形状因子的测量精度在实验和理论方面都具有重要意义！

预期精度～ 10%，略好于 BaBar，但远不如 JLab（～ 1%）

first time extraction without any assumption.δ|R

EM|/|R

EM| ~ 9% - 35%

δ|GM|/|G

M| ~ 3% - 9%

δ|GE|/|G

E| ~ 9% - 35%

15%15%

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在 BESIII 上测量质子形状因子

Assuming STCF has a luminosity 100 times higher than that of BEPCII, MC study shows a precision comparable to JLab can be achieved. Example @ 2.23 GeV:

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在 STCF 上测量质子形状因子

Nsig REM/REM / Luminosity (pb-1)

comment

614±24 24% 3.9% 2.631 BESIII test run

3881±62 9.5% 1.6% 16.630 BESIII expected

156253±395 1.5% 0.25%

669.533 STCF reach 1

389898±624 0.96% 0.16%

1670.69 STCF reach 2

STCF reach 1 STCF reach 2

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Diptimoy Ghosh

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Diptimoy Ghosh

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Charmonium• Reasonably well understood below open charm. However,

information about decays of low-lying states is very incomplete (e.g. only 40% of hadronic decays of J/y is known).

• Many unknown above the open charm.

Not well understood

Reasonably well understood

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Precision Measurement• Precision measurement of probabilities for transition

between low-lying levels of charmonium, their masses, total and leptonic or two-photon widthsCompare with the predictions from potential quark models, LQCD

• Measure probabilities of rare, not yet discovered electric/magnetic dipole transitions Electric - hc(2S)ghc 2.5x10-3

- y(3770)gcc0 2x10-4 Magnetic - y(2S)ghc(2S) 5x10-4

- hc(2S)gJ/y 3x10-5

- hcgcc0 10-6

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XYZ-like Particles

• High statistics data at y(4040), y(4160) y(4200?) y(4400) gccJ(2P)

• Direct production of Y(4260), Y(4360), Y(4660) -scan from 3.8 to 5.0 GeV 100 fb-1

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Search for Weak Charmonium Decays

csW+ ~10-8

• Semileptonic: J/yDs(D*s) ln

• Hadronic decay: J/yDs+r-, Ds

*+p-

DS=0 process (SM suppressed) - 10-11

• J/yD0p0, D0r0

ccss (with W exchange, C parity violating)• J/y ff 10-8

10-9

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Search for CPV, LFV Processes

One of physical effects BSM is the existence of the non-zero electric dipole moment (EDM) of quarks or leptons leading to CPV

• J/ygff c quark EDM at 10-15 e-cm level

• J/yLL set limit ~10-19 e-cm for EDM of L (two order of magnitude more stringent)

Lepton flavor violation• J/yll’ (l,l’=e, m, ) < t 10-9

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Light Hadron Spectroscopy• Systematically study spectroscopy of states of light

quarks.

• Search for bound states of two gluons, glueballs, and hybrid states, qqg, multi-quark states. Glueball: J/y radiotive decay, two-photon meson production Hybrid: p1(1400), p1(1600)

- Exotic(JPC= 1-+): search for S-wave decay cc1pp1, P-wave

decay J/yrp1 - Noe-exotic(JPC= 0-+): cc0pp1, y decays

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Physics with D Mesons

Advantage as compared to SBF• Low multiplicity—low background• Threshold effect• Produce in a quantum-coherent state, with - JPC=1-- for e+e-DD - JPC=0++ for e+e-gDD

SCTF• 109 pairs of charge and neutral D mesons• 107 pairs of Ds mesons

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The D-meson States and Their Transition

• Experimental information is incomplete. • The quantum numbers for most of them are not established. • Almost no information about their decay modes. • The masses of the DsJ mesons lie well below the predictions of the quark model hypotheses for six-quark or molecular DsJ structure.

Production• 4.3-5 GeV:

• 5-6 GeV - DsJ(2632), DsJ(2708), DsJ(2860) - New states

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Charmed Meson Decays

• Precision measur. of leptonic, semi-leptonic decays of D and Ds• Measure fD, fDs to better than 0.5% • The difference between the experiment and the SM calculation

may indicate physics BSM.

CLEOC

SM gives:

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D0-D0 MixingEigenstates of the mass matrix: Two non-dimensional parameters:

Results from BF

With 10 ab-1 data at SCTF, a precision of measuring mixing parameters can compete with that from SBF.

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Search for CPV • Search for CPV in D decay—one of the most interesting

project at SCTF• SM predict a very small CP asymmetry in charm sector—10-3 is

expected in the Cabibbo-suppressed (CS) D decays. • Observation of a CP asymmetry in CF and DCS decays at any

level or an asymmetry higher than 10-3 in CS decays will clearly indicate the presence of new physics BSM.

Current values of CP asymmetry measured in D decays

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D Meson Rare Decays• Rare decays of D mesons are a tool for a search for

new physics BSM.• Most suitable for: - flavor-changing neutral current (FCNC) decays via the weak neutral current, providing the transition between c and u quarks. SM suppressed - lepton-flavor-violating (LFV) decays - lepton-number-violating (LV) decays SM forbidden

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Rare Decays of D• 10-8 for transition of cul+l- and cug. Increased to

10-5 considering large distance dynamics.

Experimental upper limit on rare D and Ds decays in unite of 10-6

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Charmed Baryons• First observed in 1970s• Observed mass range: 2.3-2.7 GeV • Evidence of doubly charmed meson Xcc at 3.52 GeV

from SELEX • Predicted triply charmed baryon Wccc, but not yet

observed.• There is practically no experimental information

about the quantum numbers of baryons and absolute branching fractions of their decays.

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Parameters of the S-wave Charmed Baryons

• Mainly from BF, 107 LcLc

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Physics with t Leptons• e+e-t+t- near threshold -- low and controlled background• Precision measurements of as, ms, Vus

• Lepton universality: mt, tp+nt and tK+nt

• Lorentz structure of the amplitude for tlnlnt

• Search for LFV processes: tl , g lll’, lh – sensitive to new physics (10-7-10-8 from BF)• Search for CPV: ACP = (G(tf+) - G(tf-)) / (G(tf+) + G(tf-)) Most promising processes tKp0nt, rpnt, wpnt, a1pnt Observation of CP asymmetry would be an explicit indication of physics BSM.• Competition from SBF, but threshold effect is important for

controlling and understanding background• Longitudinal polarization of the initial beams will significantly

increase sensitivity in searches for CPV in lepton decays.

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R-values and QCD • R (1%), s and mc

• Quark and glue fragmentation functions

• Form factors: p, ……p

• Important test of QCD: Modified Leading Log

Approximation/Local parton-hadron duality (MLLA/LPHD)

- distribution (=-ln(2p/s), parameter L &

KLPHD

- Multiplicity, 2nd binomial moment R2

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HIEPAF: Accelerator • Peak luminosity: 1 x 1035 cm-2s-1 at Ecm=4 GeV

• Energy range: Ecm=2–7 GeV • Polarization available on one beam?• Symmetric machine with low currents and crab

waist solution for the interaction region • Interdisciplinary mode for - ring: compatible with synchrotron radiation facility (SRF) - linac: free electron laser (FEL)