Hadron Experiments in the Framework of Medium Energy Physics Topical KHuK-Meeting GSI, Klaus Peters Ruhr-Universität Bochum

Klaus Peters - Topical KHuK-Meeting - GSI 2 Open problems Confinement qq(bar)-Potential,... Gluonic Degrees of Freedom glueballs and hybrids,... Origin of Mass chiral aspects,... Others

Klaus Peters - Topical KHuK-Meeting - GSI 3 One for all Confinement Gluonic DoF Origin of Mass Others no direct complication due to light quarks narrow states non-pertubative effects tend to be “smaller corrections“ to the pertubative results transition between the two worlds C HARM- P HYSICS

Klaus Peters - Topical KHuK-Meeting - GSI Light Mesons are complicated naive quark-antiquark- picture is wrong for light mesons “leading“ meson-term is only the simplest of many Fock-states exception: narrow states (small mixing of states) exotic quantum numbers (reduce density of states)

Klaus Peters - Topical KHuK-Meeting - GSI 5 Further Options Experiments with open charm production are suitable to address other questions in addition mixing and CP-violation in the charm-sector rare charm-decays charmed baryons...

Klaus Peters - Topical KHuK-Meeting - GSI 6 (uds-Quarks) Experiments in the light meson sector Hall-D (Jlab), CB (Elsa),... Compass (CERN) - and K-Beams (JHF?,MPS?) p-Beams (Cosy) Many ambiguities for the interpretation density of states (large) width of states (large) mixing of states (may be large)

Klaus Peters - Topical KHuK-Meeting - GSI Central Production CERN-experiments: WA76, WA91, WA102 Important results in the scalar (,KK,K s K s,4) tensor (,KK,K s K s,4) pseudoscalar (,) sectors But:  ~ 1/M 2 no charm-sector partial wave (moment)- analysis complicated little , statistics Future: Compass, much higher statistics

Klaus Peters - Topical KHuK-Meeting - GSI Exotic-Production via FSI

Klaus Peters - Topical KHuK-Meeting - GSI 9 Current and Proposed Experiments (c-Quarks) Earlier Charm-Experiments like FNAL E687, E791 and E835 (- resp. -induced) reached their systematic limit... phasing out “new“ dedicated Charm-Experiments BES-III, CLEO-C, “Hera-C“ und HESR

Klaus Peters - Topical KHuK-Meeting - GSI CLEO-C Leptonic charm-decays Dl and D s l (f D, f Ds ) Semileptonic charm-decays D(K,K*)l, D ()l, Ds()l, D s (K,K*)l and  c l (CKM) Hadronic charm-decays DK, D ± K, D s  (Normalisation) Rare decays Mixing CP-Violation Quarkonia: light mesons, charmonium (vector) Radiative J/-decays Multihadron J/-decays Precision measurement R on three spots (~2%) electroweak(g-2)

Klaus Peters - Topical KHuK-Meeting - GSI 11 Current and Proposed Experiments (b-Quarks) B-factories Babar and Belle Hadronic B-factories Hera-B, bTeV and LHCb Super-B-factories Super-Babar huge charm production rates but !

Klaus Peters - Topical KHuK-Meeting - GSI Comparison  cf and B-Factories SensitivityCLEO-CBaBar 2-4 fb fb -1 f D |V cd |1,5-2%10-20% f Ds |V cs | 1% 5-10% (DK)/ D 1.5%3-5% (Ds)/ Ds 2-3%5-10% (Dl)/ D 1,4%3% ( c pK)/ c 6%5-15% A CP ~1% x‘ (mix)0,01 statistics limited systematics limited

Klaus Peters - Topical KHuK-Meeting - GSI 13 First Shootout CLEO-C dominates all e + e - -Projects in the charm-sector statistics > O(10-100) (BES, Babar, Belle) signal-to-background-ratio (Super-Babar) High energy experiments high charm yields very good vertex resolution (for open charm) bad mass resolution (20-50 MeV) problems with exclusive channels

Klaus Peters - Topical KHuK-Meeting - GSI Mass Resolution of Hadronic B-factories Mass resolution is rather poor – for spectroscopy (high momentum tracks) Charmonium-Physics excluded Open Charm: rare decays bTeV: B  D s K  M =24 MeV Hera-B: J/  +  -  M =54 MeV

Klaus Peters - Topical KHuK-Meeting - GSI 15 Confinement Charmonium-Spectrum Structure charmonium spectrum dominated by V(r) ~ a/r + br FS and non- pertubative effects change individual states

Klaus Peters - Topical KHuK-Meeting - GSI LQCD-Potentials Comparison between quenched/unquenched shows compatibility for bbbar-Potentials  fD (stat) = 1% unquenched calc: 200 PCs for 3 months Vital field with large algorithmic improvements and improved systematic corrections

Klaus Peters - Topical KHuK-Meeting - GSI 17 Spectroscopy of Light Mesons No/small problem with statistics Interpretation biased by models (poles, couplings) Problem: interpretation of measured states less precise predictions density of states with of states mixing of states

Klaus Peters - Topical KHuK-Meeting - GSI 18 Open Problems in Charmonium Unclear and missing States (mainly singlet)  c ‘ unconf. (CBall) h c unconf. (E760) d-States unknown 1 D 2 can not be populated by radiative transitions nothing known above DDbar-thresholds -Levelstructure Decays Helicity violation e.g. in 0 -+ Proton-Antiproton strange decay pattern for (4040) partial widths mostly unknown Others precise measurement R = N( +  - )/N(had.) a.o.m.

Klaus Peters - Topical KHuK-Meeting - GSI 19 CLEO-C Process e + e -   (n)  xy Only J PC = directly accessible other states only via decays Precision measurement of R and many exclusive J/, (3770) und ~(4140) radiative J/-decays Expected statistics 10 9 J/ 3 x 10 7 DDbar 1,5 x 10 6 D S - D S +

Klaus Peters - Topical KHuK-Meeting - GSI 20 HESR Process pp   (n)  xy (Formation) All J PC accessible Formation from an initial fermion-antifermion- system Understanding the annihilation process is not mandatory, since only the decays are of interest Line of attack: Non-Vector-Sector Mandatory: very cold beam with p/p = 10 -5

Klaus Peters - Topical KHuK-Meeting - GSI 21 Gluonic Degrees of Freedom (1) Hybrids Gluonic excitations of the quark-antiquark- potential may lead to bound states LQCD: m H ~ GeV Light charmed hybrids could be as narrow as  O(5-50 MeV) selection rules # charmed final states (Zweig-Rule)

Klaus Peters - Topical KHuK-Meeting - GSI Density of states (e.g. for Vector Mesons) Light mesons have usually larger widths Since N Q =3 (uds) combinatorics yields very many states Ideal: charm-Sector with a much reduced density of states

Klaus Peters - Topical KHuK-Meeting - GSI 23 Charmed Hybrids Fluxtube-Modell predicts DD** decays ifm H <4,29 GeV   H <50 MeV Some exotics can decay neither to DD nor to DD* e.g.: J PC (H)=0 +- fluxtube allowed J/f 2, J/() S,h 1c  fluxtube forbidden  c0 , c0 ,  c2 , c2 ,  c h 1 Small number of final states with small phasespace CLEO-II B  J/  K (S) (±)

Klaus Peters - Topical KHuK-Meeting - GSI Exotic Production in Proton-Antiproton High production yields for exotic mesons (or with a large fraction of it) f 0 (1500)  ~25 % in 3  f 0 (1500)  ~25 % in 2   1 (1400)  >10 % in      Interference with other (conventional) states is mandatory for the phase analysis

Klaus Peters - Topical KHuK-Meeting - GSI Charmonium Yields in Proton-Antiproton J PC M [MeV]  tot [MeV] decay  M [pb]* E./Day ** (L=10 32 cm -2 s -1 ) cc ,2  5502,2k  ,4k c‘c‘ ?  1200,5k >> >>1k ?  c ,88 J/ ,4k  c ,0 J/ ,8k HcHc ? J/ ~100>~1k HcHc ? J/ ~10>~0,1k --E760- J 120~1k * in this decay branch (peak yield) ** = 8 pb -1 /day

Klaus Peters - Topical KHuK-Meeting - GSI 26 Hybrid Formation in in Proton-Antiproton Gluon rich process creates gluonic excitation in a direct way since ccbar requires the quarks to annihilate (no rearrangement) yield comparable to production of charmonium 2 complementary techniques Formation (Broad- and Fine-Scans) Production (Fixed-Momentum) Momentum for an complete survey p~15 GeV

Klaus Peters - Topical KHuK-Meeting - GSI Mass regions and p momentum Neccesary momentum span is driven by the charm-exotics Hybrids (H C ) H C non-exotic J PC Formation 10 GeV/c H C exotic J PC Production 15 GeV/c (+Recoil-Particle+Phsp.) D (s) -Hybrids D s D s +1 GeV/c ~12 GeV/c Charmed Multiquarks (M C ) M C l + l - 15 GeV/c

Klaus Peters - Topical KHuK-Meeting - GSI Continuation of Experiments First experiments: CERN Same technique: TeV-Booster ‘til Y2k Many contributions to the field of charmonium physics but: momentum limited to 9 GeV no measurements above open charm threshold no 1 D 2, 3 D 2 (both narrow since DDbar forbidden) detector limitations small solid angle no charged tracking, no , small luminosity FNAL focused on HEP and Post-SM physics

Klaus Peters - Topical KHuK-Meeting - GSI 29 Hybrid Formation with -, K- and -Beams Meson formation via meson exchange prozess coupling through decay channels only light hybrids possible decay channels usually unknown, their partial width could be awfully small

Klaus Peters - Topical KHuK-Meeting - GSI 30 Gluonic Degrees of Freedom (2) Glueballs Light gg/ggg-systems are complicated to identify Exotic heavy glueballs m(0 +- ) = 4140 (50)(200) MeV m(2 +- ) = 4740 (70)(230) MeV Width unknown, but! nature invests more likely in mass than in momentum Flavour-blindness predicts decays into charmed final states Same run period as hybrids In addition: scan m>2 GeV/c 2 Morningstar und Peardon, PRD60 (1999) Morningstar und Peardon, PRD56 (1997) 4043

Klaus Peters - Topical KHuK-Meeting - GSI 31 Glueballs: Further Production Experimente Light Glueballs (J PC =0 ++, 0 -+ und 2 ++) ideal: in radiative J/Decays: J/  X where X can be analysed in many exclusive channels CLEO-C N(J/) = 20 x BES = 200 x MIII alternatively D (S)  3 PS (only scalar waves) N(D S )= O(10) x B-Fab

Klaus Peters - Topical KHuK-Meeting - GSI 4-Quark Formation with DiLepton-Tag Proton-Antiproton contains already a 4-Quark-System Idee: Dilepton-Tag from Drell-Yan-Production Advantages trigger less J PC -Ambiguitäten GeV GeV antiproton-Beam (für L=10 32 cm -2 s -1 )

Klaus Peters - Topical KHuK-Meeting - GSI 33 Origin of Mass Influence of the Nuclear Medium Pionic atoms, exhibit mass shifts in the nuclear medium Continue with charm Experimental aspects enhanced D-Production at threshold Broadening of the (3770) (2040 MeV) or  c2 (0,322,7 MeV) (DiLepton-Channel) Andvantages in antiprotonic production T~0 (not like Heavy-Ion) Hayaski, PLB 487 (2000) 96 Morath, Lee, Weise, priv. Comm. recent GSI measurements

Klaus Peters - Topical KHuK-Meeting - GSI 34 Measureable Effects

Klaus Peters - Topical KHuK-Meeting - GSI 35 J/-Absorption in the nucleus Indications for Quark-Gluon-Plasma  J/ attenuation in heavy-ion collisions Experiments at GSI: DiLepton-spectrometer Hades Problem: ccbar-interaction in the nucleus unclear Existing material from photoproduction ambiguous For further investigations a direct measurement of the basic reaction is mandatory Proposed reaction pbar (~4 GeV/c) + A  J/ + (A-1)

Klaus Peters - Topical KHuK-Meeting - GSI 36 J/N in Proton-Antiproton-Reactions No competition - unique source Fermi-smeared ccbar-Produktion J/, ‘ or interference region selected by pbar-Momentum Longitudinal und transverse Fermi- distribution is measurable

Klaus Peters - Topical KHuK-Meeting - GSI 37 Further Possibilities Charm experiments have additional capabilities apart from the addressed problems in QCD Mixing and CP-violation in the D-system exclusive decayrates, leptonic and semileptonic decays (f D (s) ) rare decays (SM and beyond) Hadronic factories may contribute to specific rare decays (may need special triggers) like Hera-B/C: D 0  +  - Questionable: how does this fit into their schedule? Future: bTeV und LHCb For CP-violation and mixing: Coherent pair-Production more appropriate

Klaus Peters - Topical KHuK-Meeting - GSI 38 Mixing and CP in the D-Meson-Sector small mixing in the charm Sector compared to K 0 and B (S) 0 Interference of amplitudes may lead to CP-Violation Measure D + /D — -asymmetries

Klaus Peters - Topical KHuK-Meeting - GSI 39 Experimental Approach Direct CP-Violation  CP ~ reconstructed DD- pairs needed (3) Realistic: (D rec. ) CLEO-C: 3x10 7 DD/y HESR: 2,5x10 7 DD/y FOCUS: 10 6 D/y B-Fabs: <10 7 DD/y only ccbar- Fragmentation usable, still large background CLEO-C and HESR same capabilities CLEO-C is advantageous in terms of background, but CESR-C is symmetric and limit HESR need specific triggers, but luminosity upgrades may improve the overall situation  CHALLENGE

Klaus Peters - Topical KHuK-Meeting - GSI Charm-Threshold Example: CLEO-C Large cross section with small particle multiplicity Clean initial state coherent D-pairs Tagging possibilities Very good neutrino- reconstruktion (Missing-Mass- Technique)

Klaus Peters - Topical KHuK-Meeting - GSI 41 Summary (1) Completeness All problems can be addressed with the proposed experiments: Confinement (-potential) CLEO-C (only 1 -- ), HESR (all ccbar) Gluonic Components CLEO-C (light gg), HallD (uds-Hybrids), HESR (heavy gg, c-Hybrids [uds-Hybrids]) Nucleare Interaction HESR (D-Mass shift, J/-Absorption)

Klaus Peters - Topical KHuK-Meeting - GSI Annihilation in Flight – no longer a challenge! Crystal Barrel has prooven the that annihilation in flight can be analyzed unambiguously Formation: twobody decays, where at least one particle carries spin! Production: integration of the production process or small recoil momenta may reduce the available phsp. and the contributing waves dramatically Peters, NPA 692 (2001)295

Klaus Peters - Topical KHuK-Meeting - GSI Timescale (Guestimate) Babar/Belle? SuperBabar BES IIBESIII CLEO-III/-C CLEOIIICLEOC ? HallD HESR Hera-B/C HERAB ? bTeV /LHCb

Klaus Peters - Topical KHuK-Meeting - GSI 44 Summary (2) Interpretation–What do we learn LatticeQCD and PT are the framework for a complete interpretation of the proposed results In the last 5 years LQCD has made an enormous step forward because of improved knowledge and algorithms, rather than in hardware - still improving New projects allow high precision tests/calibration High-precision and broad range is essential to differentiate LGT from models

Klaus Peters - Topical KHuK-Meeting - GSI 45 Summary (3) Complementarity-Uniqueness High statistic projects CLEO-C and HESR overlap in charm CP/mixing-physics CLEO-C focuses on open charm production and decays and J/-physics HESR focused on uncompromised charmonium production and other heavy exotic States HESR has also the unique opportunity to measure effects of charm in the nuclear medium

Klaus Peters - Topical KHuK-Meeting - GSI 46 Post Scriptum Charm-Physics is an outstanding window to the world of QCD