Hybrids and Glueballs in the light of antiproton reactions pBar
Workshop GSI, 5.4.2002 Klaus Peters Ruhr-Universitt Bochum Slide 2
5.4.2001Klaus Peters - pBar Workshop - 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 (reduced density of states) Slide 3 5.4.2001Klaus Peters -
pBar Workshop - GSI 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 width of states mixing of states Slide 4
5.4.2001Klaus Peters - pBar Workshop - GSI Exotic-Production via
FSI Slide 5 5.4.2001Klaus Peters - pBar Workshop - 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 Slide 6
5.4.2001Klaus Peters - pBar Workshop - GSI Gluonic Degrees of
Freedom - Hybrids Gluonic excitations of the
quark-antiquark-potential may lead to bound states LQCD: m H ~
4.2-4.5 GeV Light charmed hybrids could be as narrow as O(5-50 MeV)
selection rules small # of charmed final states (Zweig-Rule) Slide
7 5.4.2001Klaus Peters - pBar Workshop - GSI Charmed Hybrids
Fluxtube DD**, but if m H 5.4.2001Klaus Peters - pBar Workshop -
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
Exotics are present ! Slide 10 5.4.2001Klaus Peters - pBar Workshop
- GSI Hybrid Formation in in Proton-Antiproton Gluon rich process
creates gluonic excitation directly since ccBar requires the quarks
to annihilate (no rearrangement) yields comparable to production of
excited charmonium 2 complementary techniques Formation (Broad- and
Fine-Scans) Production (Fixed-Momentum) Momentum for an complete
survey p~15 GeV Slide 11 5.4.2001Klaus Peters - pBar Workshop - 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 D (s) -Hybrids D s D s +1
GeV/c ~12 GeV/c Charmed Multiquarks (M C ) M C l + l - 15 GeV/c
+Recoil-Particle +Phsp. Perfect Resolution Slide 12 5.4.2001Klaus
Peters - pBar Workshop - GSI Gluonic Degrees of Freedom - 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) 034509 Morningstar und
Peardon, PRD56 (1997) 4043 Slide 13 5.4.2001Klaus Peters - pBar
Workshop - GSI 4-Quark Formation with DiLepton-Tag
Proton-Antiproton contains already a 4-Quark-System Idea:
Dilepton-Tag from Drell-Yan-Production Advantages trigger less J PC
-Ambiguities 1200 E./day @ 12 GeV/c 300 E./day @ 5-8 GeV/c
antiproton-Beam (for L=10 32 cm -2 s -1 ) Slide 14 5.4.2001Klaus
Peters - pBar Workshop - GSI Lessons from LEAR Full solid angle no
missing particles (photons!) Low threshold electromagnetic detector
K S -Trigger Kaon ID @ high Energies EE 3030 E min cos Slide 15
5.4.2001Klaus Peters - pBar Workshop - GSI Annihilation in Flight
no longer a challenge! Crystal Barrel has prooven that the
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 Slide 16 5.4.2001Klaus
Peters - pBar Workshop - GSI Channels, Signatures, Potential
Problems Leading charmonia J/, , ( ) c, cj [DDbar] a.o.m.?
DiLeptons e + e - (Ecal,Trk) [ c.m.: usually fast, but slow for
4-Quark-Tag ] + - (Trk,Hcal) Photon-Pairs from ccBar (Ecal,no-Trk)
from 0 and (Ecal) ()-Tag and recoil (Trk,Cherenkov) Most
information needed on trigger level ! Slide 17 5.4.2001Klaus Peters
- pBar Workshop - GSI Required Features Usual omni purpose features
Forward spectrometry: cos1 for low multiplicity charged final
states [low and medium energy scans] Mandatory! Fast particle id
(guess) for trigger purposes [hard and/or soft] Threshold
Cherenkov? In addition to a multi purpose device (DIRC)? Slide 18
5.4.2001Klaus Peters - pBar Workshop - GSI Summary Exotics are
present in proton-antiproton reactions Light exotics are
complicated to measure and to classify Heavy exotics will show a
clearer signature Charged and neutral tracking together with
efficient particle id e / m / and /K and V 0 -finder is mandatory
Exclusiveness with flat efficieny for the full solid angle
