Canisius Medium Energy Nuclear Physics
Investigating the Subatomic World
What is Nuclear/Particle Physics?
The strong nuclear interaction is responsible for binding the smallest nuclear particles, quarks, into composite particles called hadrons. Hadrons are grouped into two categories:
- Baryons - nuclear particles with three quarks. The most common examples are protons and neutrons.
- Mesons - nuclear particles with two quarks or more precisely a quark and an anti-quarks. The lightest of the mesons are the pions, with masses about 7 to 8 times smaller than a proton.
The quarks come in six flavors: up, down, strange, charm, top, and bottom. Quarks also carry a nuclear charge called color. There are three color charges labelled red, blue, and green. There are also color anti-charges of anti-red, anti-blue, and anti-green.
A hadron must be color neutral by containing quarks with all three colors or by quark/anti-quark pairs that give a total color charge of zero.
The myriad of quark combinations into hadrons is cataloged by the Particle Data Group at the Lawrence Berkeley Lab.
An excellent description of the Standard Model of Particle Physics can be found in section 5 of Modern Physics in The Physics Hepertextbook.
What is CMENP?
The Canisius Medium Energy Nuclear Physics (CMENP) is a research group in the Department of Physics at Canisius College in Buffalo, NY. The group consists of Dr. Michael Wood and a team of undergraduate students.
The goal of the group is to conduct cutting-edge research of the behavior of quarks in hadrons. Currently, our research is divided into two projects:
Modification of hadrons in the nuclear medium
We know that hadrons are made up of quarks. A lot of our knowledge about the properties of hadrons has come from studying reactions of the hadrons produced from a proton. Our group is investigating whether those hadronic properties will change when the hadron is inside of a nucleus. Does the cloud of quarks that make up the nucleus alter the mass, width, and interactions of the hadrons as they traverse the nucleus? Specifically, we are studying the behavior of the long-lived mesons, like the neutral kaon, in heavy nuclei, such as Fe and Pb.
Quark Confinement and Hadronization
Quark confinement is the explanation of why we do not observe free quarks. At cold temperature, like those in an atomic nucleus, the quarks condense into protons and neutrons. When a quark is liberated from a proton, the energy released by the nuclear bonds creates quarks and anti-quarks from the vacuum. This mix of quarks will produce a proton and a new hadron. This process of forming color-neutral hadrons from free quarks is called hadronization. Our group is investigating quantitatively the hadronization of massive mesons like the omega and the f1.
Thomas Jefferson National Accelerator Facility (JLab)
The group conducts research at JLab, a Department of Energy (DOE) laboratory in Newport News, VA. The lab consists of an electron accelerator and three experimental halls (A, B, and C). The accelerator is two linear accelerators (linacs) connected to two sets of recirculating arcs. This arrangement allows for electron beam energies from 500 MeV to almost 6 GeV. More information can be found here. The DOE upgraded the accelerator in order to double the maximum beam energy to 12 GeV. This energy upgrade has expanded the range of available hadrons to include the charm quark. The lab has also expand by adding a fourth experimental hall (D).
The existing halls upgraded their detector systems to take advantage of the expanded kinematics. The CMENP group is involved with experiments in Hall B. Before the 12 GeV upgrade, Hall B contained a photon tagger to allow for both electron and photon beams. Also, the hall contained the CEBAF Large Acceptance Spectrometer (CLAS). The CLAS had a set of six identical particle spectrometers in a ball shape with an almost 4-pi acceptance. The detector system contained drift chambers for position measurements, time-of-flight for velocity determinations, electromagnetic calorimeters for energy measurements, and Cherenkov counters for electron/pion discrimination. The CLAS is ideal for studies with multi-particle decays.
For the 12 GeV upgrade, the CLAS detector has been augmented to accommodate the forward direction of the produced particles. The new detector configuration is called CLAS12 and will have a number of new components. One new component is the Pre-shower Calorimeter (PCAL). The original electromagnetic calorimeters (EC) will be part of CLAS12 but do not have the resolution to distinguish such reactions as the decay of a neutral pion into two photons. To increase the resolution, the PCAL will be placed in front of the EC. The PCAL allows for the detection of high-momentum neutral pions, which are important for reconstructing the omega meson.
Abbey Physics
Abbey Physics is an introductory Physics textbook aimed at the high school student. The motivation behind the book is to provide an introduction to the subject that is mathematically rigorous while at the same time strips out a lot of the clutter in a standard textbook. These things are expensive glossy pictures and topics like rotational motion. This book has been used in paper form at St. Anselm's Abbey School, a private, Catholic high school in northeast Washington, D.C., where one author (Dr. Herbert Wood) has taught since 1986. In 2013, we converted it into ebook form and are offering it on Apple's iBookstore for a nominal fee. Follow this link to the bookstore. The ISBN is 978-1-62847-263-9. We hope you enjoy it and learn some Physics.
