Download Student Seminar Subatomic Physics, blok 1+2 2002/03

Student Seminar Subatomic Physics, blok 1+2 2002/03
In this seminar we plan to study topics in subatomic physics which are of high current
interest. We aim to select a menu that is highly relevant for the various research groups at
the KVI and educative also for masters students not (yet) affiliated to the KVI. The
literature will consist mostly of actual research overview articles supported by chapters
from textbooks. The selection of literature should be discussed with the supervisor of the
respective seminar contributions.
Chapter 1: New results in neutrino physics
Recently, new results from the Sudbury neutrino observatory and the Super Kamiokande
collaboration proved that neutrino’s must have mass, in contrast to the standard concept of weak
interactions. The reason that we know they have mass is due to the fact that neutrino’s of one type
can convert into another type. In the seminar we want to discuss basic concepts behind neutrino
conversion, i.e. neutrino oscillations and the MSW effect (1). The Sudbury neutrino observatory
(SNO) was the first detector that could measure both neutral current and charged current neutrino
interactions which allowed for the first time a direct proof of the conversion of electron neutrino’s
into other types of neutrino’s. In the seminar we will discuss the superior detection concept of the
SNO detector in relation to the different neutrino interactions (2). Although we know now that
neutrino’s of each type have a different mass at least one mass needs to be measured on an
absolute scale, all other’s we can derive via the oscillation observables. Absolute neutrino mass
measurements have been attempted by looking in detail at the beta energy spectrum from tritium
decay. In the seminar we will address the basic problems and techniques associated with beta
decay (3). Now that the neutrino is known to have mass it has become more important to know if
the neutrino is its own antiparticle or not. This is issue is addressed in the neutrino-less double
beta decay. In the seminar we will discuss the controversial evidence for its observation (4).
The references below contain a website where you can get most information associated with an
experimental technique or issue and an article that you should focus on if you wish to discuss one
of the four topics given above. All articles can also be downloaded via the University Library
(except Physics Today).
1. Neutrino oscillations and neutrino masses
W.C. Haxton and B.R. Holstein “Neutrino Physics” hep-ph/9905257
J. Bahcall’s homepage http://www.sns.ias.edu/~jnb/ (focus on solar neutrino’s)
2. Solar neutrino results from the Sudbury neutrino observatory
a) “Before and After: How has the SNO NC measurement changed things?”
John N. Bahcall, M. C. Gonzalez-Garcia, and C. Peña-Garay hep-ph/0204314
b) Physics Today July 2002 p.13-15 and actual references
c) SNO homepage: http://www.sno.phy.queensu.ca/
3. (Absolute) neutrino mass experiment
a) Results from the Mainz neutrino mass experiment
J. Bonn et al., Progress in Particle and Nuclear Physics 48 (2002) 133-139
b) results from Troitsk experiment
Progress in Particle and Nuclear Physics 48 (2002) 123-131
1
c) plans for KATRIN (sub-eV neutrino mass)
Progress in Particle and Nuclear Physics 48 (2002) 141-150
d) web pages
Mainz http://www.physik.uni-mainz.de/exakt/neutrino/en_index.html
Katrin http://ik1au1.fzk.de/~katrin/
Troitsk http://www.inr.troitsk.ru/~trdat/
4. Neutrinoless double beta decay
“Evidence for neutrinoless double beta decay”
H. V. Klapdor-Kleingrothaus, A. Dietz, H. L. Harney and I. V. Krivosheina, ,
Modern Physics Letters A, Vol. 16, No. 37 (2001) 2409-2420, linked here.
Webpage of the experimental collaboration:
http://www.mpi-hd.mpg.de/non_acc/dblbeta.html
The exchange of comments between the pro’s and the anti’s are listed on
http://www.to.infn.it/~giunti/NU/bb/
2
Chapter 2: Approaches to nuclear structure
The atomic nucleus is a system of a large number of strongly interacting particles. Three
is in this case already a large number. Due to the strong interaction, which makes
perturbative approaches less suitable and due to the number of particles it is still a
challenge to perform a reliable calculation of nuclear properties. These calculations are of
great interest, partly because there are a large number of nuclei, partly because their
properties are crucial to understand the creation of the different isotopes, which are
essential to life, and partly because nuclei are excellent micro-laboratories for studying
fundamental symmetries. The latter is the basis of the TRIMP project at KVI.
Nuclear structure has a long history and many approaches have been developed. Most of
these are rather phenomenological. More recently emphasis is placed on so-called abinitio approaches, which start from a realistic nucleon-nucleon force. A nice overview
and quantitative comparison of the different techniques is given in
Benchmark test calculations of a four-nucleon bound state,
Kamada et al., PRC 64 (2001) 44001.
On the basis of this paper a few approaches will be discussed in more detail, in particular
the no-core shell model and the Greensfunction Monte Carlo, which focus on achieving
highest accuracy for the low-lying states. For other problems it might more desirable to
have a description of more average properties of a nucleus at finite temperature.
1. Greensfunction Montecarlo
Quantum Monte Carlo calculations of A=8 nuclei
R. B. Wiringa and Steven C. Pieper, PRC 62 (2000) 014001
2. No-core shell model
Ab Initio large-basis no-core shell model and its application to light nuclei
B. Barrett, P. Navratil, Acta Physica Polonica 33 (2002) 297-311
3. Finite temperature
Supernova-neutrino detection and the 208Pb( , ')208Pb* cross section
a) ContinuumRPA-Green’s fct. approach, Hartree-Fock, residual interactions,
N. Jachowicz and K. Heyde, Progress in Particle and Nuclear Physics 48
(2002) 39-40
b) Cross sections for neutral-current neutrino-nucleus interactions,
N. Jachowicz, S. Rombouts, K. Heyde, J. Ryckebusch, PRC 59 (1999) 3246
3
Chapter 3
New developments in hadronic particle production
QCD has emerged as the standard theory of the strong interaction. However, so far it has not been
possible to derive the (phenomenological) NN interaction from the elementary interactions
between the constituents of the nucleon, the quarks and gluons. Progress in this field requires the
understanding of both the effective NN-interaction and the properties of the nuclear constituents
(hadrons), i.e. the protons, neutrons and exchange mesons in terms of quarks, gluons and QCD. A
stringent test of hadron models requires a systematic study of baryon excitations and their
respective decay modes including strange hadrons.
Nucleon resonances are usually identified in pion-nucleon scattering or by photo-production and
partial-wave analyses. A particular challenge for hadronic models using an effective Lagrangian
are the large number of asymptotic meson-baryon final states. This prohibits a single-channel
approach (T-matrix model) which violates unitarity. Rather a coupled-channel treatment (Kmatrix approach) is required including all possible final states.
We will start this chapter by a general introduction to scattering theory (9). On the example of
Compton scattering on the proton the K-matrix approach will be introduced (10). Next we want to
discuss the nucleon-resonance analysis in photoproduction in the coupled-channel approach (11).
Finally we study the production of heavy mesons in nucleon-nucleon collisions (three-body final
state!) in a meson-exchange model (12).
1. Scattering Theory:
Lippmann-Schwinger eq., Green’s function, Born approximation,
T matrix, Bethe-Salpeter eq.
Sakurai, Modern Quantum Mechanics, Addison-Wesley 1994 p.379-399
2. Compton scattering on the proton and light nuclei in the Delta resonance
region (K Matrix approach)
O. Scholten, Acta Physica Polonica 33 (2002) 847-871
3. Vector meson production with photons and nucleon resonance analysis
in a coupled channel approach
G. Penner, U. Mosel, subm. PRC Jul 2002. 40pp., nucl-th/0207069
4. Pseudoscalar and vector meson production in NN collisions
K. Nakayama, nucl-th/0108032
4