Hadron Physics Department
Search for In-Medium Modifications of
Hadrons:
Experiments at HADES /SIS and ANKE & TOF /COSY and
Accompanying Theory
1. Physics Motivation
Chiral symmetry (and the corresponding
symmetry breaking pattern) is one governing principle of strong
interaction. It is anchored in the fundamental theory of strong
interaction -
quantum chromodynamics. Under normal conditions (i.e. in our physical
vacuum), chiral symmetry is spontaneously and explicitly broken. In
compressed and heated
nuclear matter, however, chiral symmetry becomes partially restored.
This
causes a change of the properties of hadrons. In particular, also the
effective masses of hadrons are changed.
The origin of the masses of fundamental constituents of matter
represents a major concern of contemporary particle physics. Hadrons
(protons and neutrons) carry more than 99 % of the mass of luminous
matter in the universe; the same holds for our natural environment,
where protons and neutrons are bound to a large extent in nuclei.
2. HADES experiment: basic ideas
To understand the phenomenon of "mass of
hadrons" various experiments are presently performed. One intriguing
idea is to study the decay products of particularly suited hadrons
within the environment of strongly interacting matter. For instance,
rho, omega and phi mesons represent such suitable hadrons. They can be
produced by elementary projectiles impinging on nuclei or in the
course of heavy-ion collisions. The created rho, omega and phi-mesons
decay, amongst other particles, into electron-positron (e+ e-) pairs
which leave the ambient strongly interacting medium nearly undisturbed,
thus offering a direct access to the original mass of their parent
hadrons. In such a way, in-medium hadron spectroscopy is enabled.
To some extent, one is attempting to search for a change of the
hadronic excitation spectrum by an external field (represented by its
surrounding nuclear matter). This is analog to atomic physics where
external electromagnetic fields change the spectrum, as verified by the
Stark and Zeeman effects.
3. HADES: detector design
The electromagnetic decay of a vector meson
is
a rare process. Therefore one needs special and dedicated detectors to
dig
the wanted e+e- pairs out of a huge background of
other particles. Additionally, the momentum of the electron (e-
) and the accompanying positron (e+) must be determined
with high precision. These requirements are satisfied by a ring imaging
Cherenkov counter (RICH) and highly position sensitive drift chambers
(MDCs). The scheme of the HADES detector
and further details of RICH, MDC and the superconducting magnet are
explained separately. HADES is an acronym of H igh A
cceptance D i-Electron S pectrometer; it is
installed in cave H at GSI/Darmstadt (see picture
). The heavy-ion synchrotron SIS delivers beams of ions (E ≤ 2 GeV),
protons (E ≤ 4 GeV), and a pion beam (Pp
≤
2.8 GeV/c) is available too. Beside
standard foil targets, also liquid hydrogen/deuterium targets may be
used.
4. HADES: physics programme
The primary goal of HADES it the systematic
and precise hadron spectroscopy of rho, omega and phi mesons via
the e+e- decay channel. The physics programme may be grouped in
(i) heavy-ion experiments (probing the in-medium behavior in compressed
nuclear matter),
(ii) proton and pion beam experiments with nuclear targets (probing the
in-medium behavior in near ground state nuclear matter), and
(iii) proton and pion beam experiments on proton/deuterium targets
(probing elementary reaction channels).
Besides the excellent opportunity to address many questions related to
the e+e- channel of hadronic interactions, HADES
may serve as hadron spectrometer with large solid
angle acceptance.
The experiments of the first round are explained
here .
5. Our contribution to HADES equipment
In the detector laboratory of the Institute
of
Hadron- and Nuclear Physics, the large (active surface 2.2m²)
multi-wire mini-drift chambers (MDCs)
have been built up. Six of these MDCs are arranged as hexagons and
installed
behind the superconducting magnet of HADES. Each MDC consists of 7
cathode
layers and 6 anode layers. The wires (»250
per layer, 80 µm aluminum for cathodes, 100 µm Tungsten for
field wires, 20
µm for sense wires of anodes) are inclined
by relative angles of 20 degrees from layer to layer. The smallness of
the drift cells (12x8mm 2), the accuracy of positioning the
wires ( ± 20µm)
and the mechanical
stability of the complete chambers represent a technological challenge.
The meaning of the MDCs (two in front and two behind the magnet) is to
have a position sensitive tool for precise particle tracking. This
afterwards allows the determination of the electron/positron momentum
and subsequently the mass of the parent hadron.
Our MDCs are like formula-1 race cars: the performance is running at
the limits and they need permanent care.
6. Experiments at ANKE & TOF: strange meson probes
Hadrons with strangeness, in particular
anti-kaons, are considered as alternative sensitive probes of in-medium
properties. Anti-kaons (e.g. K-) suffer, according to theoretical
predictions, a substantial decrease of their effective mass in a dense
nuclear
medium. This has inspired a series of heavy-ion experiments in the
late nineties (see below). It turned out, however, that in heavy-ion
reactions quite a lot of poorly known elementary reaction channels
are operative; therefore it is up to now a matter of debate whether
the predicted in-medium modifications directly offer themselves in the
exciting findings. From this, supported by detailed calculations, the
idea has arisen to study K- production in proton nucleus collisions.
Here much fewer channels are operative and the nucleon density does
not change as abruptly as in heavy-ion-collisions.
The spectrometer ANKE at the internal beam of the
cooler synchrotron COSY/FZ Jülich offers the unique opportunity
to study anti-kaon production, in conjunction with kaons, in
proton-nucleus collisions near and below the threshold. Previously, we
have built in our detector laboratory the large start and stop wire
chambers for ANKE and supplied further special equipment ar well.
The time-of-flight spectrometer TOF uses the extracted beam from COSY.
Together with colleagues from TU Dresden we built a start detector
system and equipped the large barrel. At TOF, we are interested in
measuring kaons in conjunctron with hyperons in proton-proton
reactions.
7. The origin of our experimental expertise
While focusing now on hadron physical
investigations at HADES/SIS and supplementary at ANKE & TOF/COSY,
in the
past our activities were spread over investigations of strangeness
degrees of freedom and electro-magnetic signals in colliding hadron
systems in various collaborations. The physics motivation and gained
results are described here .
8. Theory
The theory group in the hadron physics
department is accompanying these experimental activities. Predictions
and interpretations of selected topics in the field of strange and
rare electromagnetic probes are provided. Most of these calculations
refer directly to the experiments performed with FZR participation. Our
tools are QCD sum rules, effective hadronic interaction Lagrangians and
transport models. Additionally we deal with various phenomenological
aspects of deconfined matter, as a state with chiral symmetry
restoration in the strongly interacting medium, produced in high-energy
heavy-ion reactions. Whereas the investigations of dense and hot
hadronic matter, produced in medium-energy collisions, are of strong
interest for
the understanding of astronomical objects like supernovae and neutron
stars, the studies of deconfinement effects are of relevance for more
violent scenarios like the big bang.
9. Relation to
other research methods in FZR
Scientific Staff:
Ph. D. Students:
Publications 2003
Andronic, A.; Reisdorf, W.; Herrmann, N.; Crochet, P.; Barret,
V.; Basrak, Z.; Bastid, N.; Berek, G.; Caplar, R.; Devismes, A.;
Dupieux, P.; Dzelalija, M.; Finck, C.; Fodor, Z.; Gobbi, A.; Grishkin,
Yu.; Hartmann, O. N.; Hildenbrand, K. D.; Hong, B.; Kecskemeti, J.;
Kim, Y. J.; Kirejczyk, M.; Koczon, P.; Korolija, M.; Kotte, R.;
Kress, T.; Lebedev, A.; Lee, K. S.; Leifels, Y.; Lopez, X.;
Merschmeyer, M.; Neubert, W. ; Pelte, D.; Petrovici, M.; Rami,
F.; Schauenburg, B. de; Schuettauf, A.; Seres, Z.; Sikora, B.; Sim, K.
S.; Simion, V.; Siwek-Wilczynska, K.; Smolyankin, V.; Stockmeier, M.;
Stoicea, G.; Tyminski, Z.; Wagner, P.; Wisniewski, K.; Wohlfarth, D.; Yushmanov,
I.; Zhilin, A.
Directed flow in Au+Au, Xe+CsI and Ni+Ni collisions and the
nuclear equation of state
Phys. Rev. C 67 (2003) 034907
Zhu, L.Y.; Arrington, J.; Averett, T.;Beise, E.; Calarco, J.;
Chang,
T.; Chen, J.P.; Chudakov, E.; Coman, M.; Clasie, B.; Crawford, C.;
Dieterich,
S.; Dohrmann, F.; Dutta, D.; Fissum, K.; Frullani, S.; Gao, H.;
Gilman,
R.; Glashausser, C.; Gomez, J.; Hafidi, K.;
Hansen,
O.; Higinbotham, D.W.; Holt, R.J.; de Jager, C.W.; Jiang, X.; Kinney,
E.;
Kramer, K.; Kumbartzki, G.; LeRose, J.; Liyanage, N.; Mack, D.;
Markowitz,
P.; McCormick, K.; Meekins, D.; Meziani, Z.E.; Michaels, R.; Mitchell,
J.;
Nanda, S.; Potterveld, D.; Ransome, R.; Reimer, P.; Reitz, B.; Saha,
A.;
Schulte, E.C.; Seely, J.; Sirca, S.; Strauch, S.; Sulkosky, V.;
Vlahovic,
B.; Weinstein L.B.; Wijesooriya, K.; Williamson, C.; Wojtsekhowski, B,;
Xiang,
H., Xiong, F.; Xu, W.; Zeng, J.; Zheng, X.
Cross section measurement of charged pion photoproduction from
hydrogen
and deuterium
Phys. Rev. Lett. (2003) im Druck
Dohrmann, F.; Abbott, D.; Ahmidouch, A.; Ambrozewicz,
P.; Armstrong, C. S.; Arrington, J.; Asaturyan, R.; Assamagan, K.;
Avery, S.; Bailey, K.; Baker, O. K.; Beedoe, S.; Bitao, H.; Breuer, H.;
Brown, D. S.; Carlini, R.; Cha, J.; Chant, N.; Christy, E.; Cochran,
A.; Cole, L.; Collins, G.; Cothran, C.; Crowder, J.; Cummings, W. J.;
Danagoulian, S.; Duncan, F.; Dunne, J.; Dutta, D.; Eden, T.; Elaasar,
M.; Ent, R.; Ewell, L.; Fenker, H.; Fortune, H. T.; Fujii, Y.; Gan, L.;
Gao, H.; Garrow, K.; Geesaman, D. F.; Gueye, P.; Gustafsson, K.;
Hafidi, K.; Hansen, J. O.; Hinton, W.; Jackson, H. E.; Juengst, H.;
Keppel, C.; Klein, A.; Koltenuk, D.; Liang, Y.; Liu, J. H.; Lung, A.;
Mack, D.; Madey, R.; Markowitz, P.; Martoff, C. J.; Meekins, D.;
Mitchell, J.; Miyoshi, T.; Mkrtchyan, H.; Mohring, R.; Mtingwa, S. K.;
Mueller, B.; O'Neill, T. J.; Niculescu, G.; Niculescu, I.; Potterveld,
D. H.; Price, J. W.; Raue, B. A.; Reimer, P. E.; Reinhold, J.; Roche,
J.; Roos, P.; Sarsour, M.; Sato, Y.; Savage, G.; Sawafta, R.; Segel, R.
E.; Semenov, A. Yu.; Stepanyan, S.; Tadevosian, V.; Tajima, S.; Tang,
L.; Terburg, B.; Uzzle, A.; Wood, S.; Yamaguchi, H.; Yan-1, C.; Yan-2,
C.; Yuan, L.; Zeier, M.; Zeidman, B.; Zihlmann, B.
Hyperon--Nucleon Bound States and Electroproduction of
Strangeness on 3,4He
Prog. Part. Nucl. Phys. 50 (2003) 587
Dohrmann, F.; Abbott, D.; Ahmidouch, A.; Ambrozewicz,
P.; Armstrong, C. S.; Arrington, J.; Asaturyan, R.; Assamagan, K.;
Avery, S.; Bailey, K.; Baker, O. K.; Beedoe, S.; Bitao, H.; Breuer, H.;
Brown, D. S.; Carlini, R.; Cha, J.; Chant, N.; Christy, E.; Cochran,
A.; Cole, L.; Collins, G.; Cothran, C.; Crowder, J.; Cummings, W. J.;
Danagoulian, S.; Duncan, F.; Dunne, J.; Dutta, D.; Eden, T.; Elaasar,
M.; Ent, R.; Ewell, L.; Fenker, H.; Fortune, H. T.; Fujii, Y.; Gan, L.;
Gao, H.; Garrow, K.; Geesaman, D. F.; Gueye, P.; Gustafsson, K.;
Hafidi, K.; Hansen, J. O.; Hinton, W.; Jackson, H. E.; Juengst, H.;
Keppel, C.; Klein, A.; Koltenuk, D.; Liang, Y.; Liu, J. H.; Lung, A.;
Mack, D.; Madey, R.; Markowitz, P.; Martoff, C. J.; Meekins, D.;
Mitchell, J.; Miyoshi, T.; Mkrtchyan, H.; Mohring, R.; Mtingwa, S. K.;
Mueller, B.; O'Neill, T. J.; Niculescu, G.; Niculescu, I.; Potterveld,
D. H.; Price, J. W.; Raue, B. A.; Reimer, P. E.; Reinhold, J.; Roche,
J.; Roos, P.; Sarsour, M.; Sato, Y.; Savage, G.; Sawafta, R.; Segel, R.
E.; Semenov, A. Yu.; Stepanyan, S.; Tadevosian, V.; Tajima, S.; Tang,
L.; Terburg, B.; Uzzle, A.; Wood, S.; Yamaguchi, H.; Yan-1, C.; Yan-2,
C.; Yuan, L.; Zeier, M.; Zeidman, B.; Zihlmann, B.
Hyperon-Nucleon Bound States and Electroproduction of
Strangeness on Light Nuclei
In "MESON 2002: 7th International Conference on Meson Production,
Properties and Interaction of Mesons, Crakow, Poland", World
Scientific, New Jersey, 2003
Dutta, D.; Xiong, F.; Zhu, L. Y.; Arrington, J.; Averett, T.;
Beise, E.; Calarco, J.; Chang, T.; Chen, J. P.; Chudakov, E.; Coman,
M.; Clasie, B.; Crawford, C.; Dieterich, S.; Dohrmann, F.;
Fissum, K.; Frullani, S.; Gao, H.; Gilman, R.; Glashauser, C.; Gomez,
J.; Hafidi,
K.; Hansen, O.; Higinbotham, D. W.; Holt, R. J.; deJager, C. W.; Jiang,
X.; Kinney, E.; Kramer, K.; Kumbartzki, G.; LeRose, J.; Liyanage, N.;
Mack, D.; Markowitz, P.; McCormick, K.; Meziani, Z.-E.; Michaels, R.;
Mitchell, J.; Nanda, S.; Potterveld, D.; Ransome, R.; Reimer, P. E.;
Reitz, B.; Saha, A.; Schulte, E. C.; Seely, J.; Sirca, S.; Strauch,
S.; Sulkosky, V.; Vlahovic, B.; Weinstein, L. B.; Wijesooriya, K.;
Williamson,
C.; Wojtsekhowski, B.; Xiang, H.; Xu, W.; Zeng, J.; Zheng, X.
Nuclear Transparency with the g
n --> pip Process in 4He
nucl-ex/0305005 submitted to Physical Review C Rapid
Communications
Abdel-Bary, M.; Abdel-Samad, S.; Bilger, R.; Brinkmann,
K.-Th.; Clement, H.; Dshemuchadse, S.; Dorochkevitch, E.; Dutz, H.;
Eyrich,
W.; Erhardt, A.; Filges, D.; Filippi, A.; Freiesleben, H.; Fritsch, M.;
Geyer, R.; Gillitzer, A.; Hesselbarth, D.; Jakob, B.; Karsch, L.;
Kilian,
K.; Koch, H.; Kreß, J.; Kuhlmann, E.; Marcello, S.; Marwinski,
S.; Mauro, S.; Meyer, W.; Michel,
P.; Möller, K.; Morsch,
H. P.; Naumann, L.; Paul, N.; Richter, M.; Roderburg, E.;
Rogge, M.; Schamlott, A.;
Schmitz, M.; Schönmeier, P.; Schulte-Wissermann, M.; Schroeder,
W.; Sefzik, T.; Stinzing, F.; Sun, G. Y.; Wagner,
G. J.; Wagner, M.; Wilms, A.; Wintz, P.; Wirth, S.; Zupranski, P.
Measurement of the h production in
proton-proton collisions with the COSY time-of-flight spectrometer
Eur. Phys. J. A 16 (2003) 127
AbdEl Samad, S.; Bilger, R.; Böhm, A.; Brinkmann, K.-Th.;
Clement, H.; Dshemuchadse, S.; Eyrich, W.; Filges, D.; Freiesleben, H.;
Fritsch, M.; Geyer, R.; Hesselbarth, D.; Jakob, B.; Kilian, K.; Koch,
H.; Karsch, L.; Kress, J.; Kuhlmann, E.; Marwinski, S.; Michel, P.;
Möller, K. ; Morsch, H. P.; Naumann, L.; Richter, M.;
Roderburg, E.; Rogge, M.; Schamlott,
A.; Schmitz, M.; Schönmeier,
P.; Schroeder, M.; Schulte-Wissermann, M.; Sun, G. Y.; Steinke, M.;
Stinzing,
F.; Wagner, G. J.; Wagner, M.; Wilms, A.; Wirth, S.
Study of the reaction pp to ppp &sup0;
within 10 MeV above the threshold
Eur. Physics J. A. (eingereicht)
Mangiarotti, A.; Herrmann, N.; Maurenzig, P. R.; Gobbi, A.;
Kotte, R. ; Keczkemeti, J.; Leifels, Y.; Alard, J. P.; Andronic,
A.; Averbeck, R.; Barret, V.; Basrak, Z.; Bastid, N.; Belyaev, I.;
Bendarag, A.; Berek, G.; Caplar, R.; Crochet, P.; Devismes, A.;
Dupieux, P.; Dzelalija, M.; Finck, Ch.; Fodor, Z.; Grishkin, Y.;
Hartmann, O.; Hildenbrand, K. D.; Hong, B.; Kim, Y. J.; Kirejczyk, M.;
Koczon, P.;
Korolija, M.; Kress, T.; Kutsche, R.; Lebedev, A.; Lee, K. S.; Manko,
V.; Merschmeyer, M.; Moisa, D.; Nianine, A.; Neubert, W.;
Pelte,
D.; Petrovici, M.; Plettner, C.; Rami, F.; Reisdorf, W.; Schauenburg,
B. de; Schüll, D.; Seres, Z.; Sikora, B.; Sim, K. S.; Simion, V.;
Siwek-Wilczynska, K.; Smolyankin, V.; Stockmeier, M.; Stoicea, G.;
Vasiliev,
M.; Wagner, P.; Wisniewski, K.; Wohlfarth, D.; Yang, J. T.;
Yushmanov,
I.; Zhilin, A.
Subthreshold Phi-meson yield in central Ni - Ni
Nucl. Phys. A 714 (2003) 89
Kanaki, K.
Electric Field and Drift Characteristics Studies for the
Multiwire Chambers of the Third Plane of HADES
Wissenschaftlich-Technische Berichte / Forschungszentrum
Rossendorf; FZR-365 Januar 2003
Kämpfer, B.; Titov, A.I.; Reznik, B.L.
Baryon Resonance Dynamics in pi N
--> N V Reactions Near Threshold
Nucl. Phys. A (PANIC02 Proceedings)
Gallmeister, K.; Kämpfer, B.; Pavlenko, O.P.
Energy loss of quarks in deconfined matter at RHIC:
photon-tagged jets, single electron and dilepton spectra from open charm
Nucl. Phys. A 715 (2003) 705
Kaptari, L.P.; Kämpfer, B.; Semikh, S.S.;
Dorkin,S.M.
Exclusive charge exchange reaction pD --> n (pp) within the
Bethe-Salpeter formalism
Eur. Phys. J. A 17 (2003) 119
Zschocke, S.; Pavlenko, O.P.; Kämpfer, B.
In-medium spectral change of omega meson as a probe of QCD
four-quark condensate
Phys. Lett. B 562 (2003) 57
Kämpfer, B.; Pavlenko, O.P.; Zschocke, S.
Probing the strange quark condensate by dielectrons from Phi
meson
decays in heavy ion collisions at SIS energies
Eur. Phys. J. A 17 (2003) 83
Kaptari, L. P.; Kämpfer, B.; Semikh, S. S.;
Dorkin, S. M.
Relativistic effects in proton-induced deuteron break-up at
intermediate energies with forward emission of a fast proton pair
Eur. Phys. J. A, nucl-th/0212062 (eingereicht)
Cleymans, J.; Kämpfer, B.; Steinberg, P.;
Wheaton, S.
System-size dependence of strangeness saturation
J. Phys. G (2003) im Druck
Cleymans, J; Kämpfer, B.; Wheaton, S.
Towards strangeness saturation in central heavy ion collisions
at high- energies
Nucl. Phys. A 715 (2003) 553
Kaptari, L.P.; Kämpfer, B.; Semikh, S.S.
Tagging the pN -> D f reaction by backward protons in p
D -> Dpspec f processes
Phys. Rev. C (Brief Report) (eingereicht)
Publications 2002 , Publications 2001 , Publications 2000 ,Publications 1999 , Publications 1998 , Publications 1997
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