The neutron is a subatomic particle, symbol
n
or
n0
, which has no electric charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons behave similarly within the nucleus, they are both referred to as nucleons. Nucleons have a mass of approximately one atomic mass unit, or dalton. Their properties and interactions are described by nuclear physics. Protons and neutrons are not elementary particles; each is composed of three quarks.
A proton is a stable subatomic particle, symbol
p
, H+, or 1H+ with a positive electric charge of +1 e (elementary charge). Its mass is slightly less than the mass of a neutron and approximately 1836 times the mass of an electron (the proton-to-electron mass ratio). Protons and neutrons, each with a mass of approximately one atomic mass unit, are jointly referred to as nucleons (particles present in atomic nuclei).
A quark is a type of elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. All commonly observable matter is composed of up quarks, down quarks and electrons. Owing to a phenomenon known as color confinement, quarks are never found in isolation; they can be found only within hadrons, which include baryons and mesons, or in quark–gluon plasmas. For this reason, much of what is known about quarks has been drawn from observations of hadrons.
In physics, a subatomic particle is a particle smaller than an atom. According to the Standard Model of particle physics, a subatomic particle can be either a composite particle, which is composed of other particles, or an elementary particle, which is not composed of other particles. Particle physics and nuclear physics study these particles and how they interact. Most force-carrying particles like photons or gluons are called bosons and, although they have quanta of energy, do not have rest mass or discrete diameters and are unlike the former particles that have rest mass and cannot overlap or combine which are called fermions. The W and Z bosons, however, are an exception to this rule and have relatively large rest masses at approximately 80GeV and 90GeV respectively.
The down quark is a type of elementary particle, and a major constituent of matter. The down quark is the second-lightest of all quarks, and combines with other quarks to form composite particles called hadrons. Down quarks are most commonly found in atomic nuclei, where it combines with up quarks to form protons and neutrons. The proton is made of one down quark with two up quarks, and the neutron is made up of two down quarks with one up quark. Because they are found in every single known atom, down quarks are present in all everyday matter that we interact with.
The bottom quark, beauty quark, or b quark, is an elementary particle of the third generation. It is a heavy quark with a charge of −1/3 e.
A strange star, also called a strange quark star, is a hypothetical compact astronomical object, a quark star made of strange quark matter.
Frank Anthony Wilczek is an American theoretical physicist, mathematician and Nobel laureate. He is the Herman Feshbach Professor of Physics at the Massachusetts Institute of Technology (MIT), Founding Director of T. D. Lee Institute and Chief Scientist at the Wilczek Quantum Center, Shanghai Jiao Tong University (SJTU), distinguished professor at Arizona State University (ASU) and full professor at Stockholm University.
David Jonathan Gross is an American theoretical physicist and string theorist. Along with Frank Wilczek and David Politzer, he was awarded the 2004 Nobel Prize in Physics for their discovery of asymptotic freedom. Gross is the Chancellor's Chair Professor of Theoretical Physics at the Kavli Institute for Theoretical Physics (KITP) of the University of California, Santa Barbara (UCSB), and was formerly the KITP director and holder of their Frederick W. Gluck Chair in Theoretical Physics. He is also a faculty member in the UCSB Physics Department and is affiliated with the Institute for Quantum Studies at Chapman University in California. He is a foreign member of the Chinese Academy of Sciences.
The Relativistic Heavy Ion Collider is the first and one of only two operating heavy-ion colliders, and the only spin-polarized proton collider ever built. Located at Brookhaven National Laboratory (BNL) in Upton, New York, and used by an international team of researchers, it is the only operating particle collider in the US. By using RHIC to collide ions traveling at relativistic speeds, physicists study the primordial form of matter that existed in the universe shortly after the Big Bang. By colliding spin-polarized protons, the spin structure of the proton is explored.
Melissa Eve Bronwen Franklin is a Canadian experimental particle physicist and the Mallinckrodt Professor of Physics at Harvard University. In 1992, Franklin became the first woman to receive tenure in the physics department at Harvard University and she served as chair of the department from 2010 to 2014. While working at Fermi National Accelerator Laboratory in Chicago, her team found some of the first evidences for the existence of the top quark. In 1993, Franklin was elected a fellow of the American Physical Society. She is a member of the CDF (Fermilab) and ATLAS (CERN) collaborations.
Young-Kee Kim is a South Korea-born American physicist and Louis Block Distinguished Service Professor of Physics at the University of Chicago. She is chair of the Department of Physics at the university.
Ann Heinson is an American high-energy particle physicist known for her work on single top quark physics. She established and led the DØ Single Top Group which first published experimental observations of the top quark, and in 1997 she co-authored a paper which laid the foundations for further investigation into the top quark.
Asoke Nath Mitra was an Indian theoretical physicist. He was a lifetime professor emeritus at Delhi University. He is known for his work in nuclear physics, particle physics and quantum field theory and in particular, for his fundamental contributions in obtaining the exact solution of the nucleon 3- body problem with separable potentials which led to the few nucleon studies, quark-recoil effect, development of an integrated dynamics of 2- and 3- body systems from nucleons to quarks as well as for the development of quark dynamics and relativistic quark models for hadrons in the Bethe-Salpeter framework. He was awarded the Shanti Swarup Bhatnagar Prize in 1969.
Heidi Marie Schellman is an American particle physicist at Oregon State University (OSU), where she heads the Department of Physics. She is an expert in Quantum chromodynamics.
Jonathan Mark Butterworth is a Professor of Physics at University College London (UCL) working on the ATLAS experiment at CERN's Large Hadron Collider (LHC). His popular science book Smashing Physics, which tells the story of the search for the Higgs boson, was published in 2014 and his newspaper column / blog Life and Physics is published by The Guardian.
David Gerdes (born 1964) is an American astrophysicist, professor, and administrator at the University of Michigan. He is known for his research on trans-Neptunian objects, particularly for his discovery of the dwarf planet, 2014 UZ224.
Paul Dutton Grannis is an American physicist.
Paraskevas Andreas Sphicas is a particle physicist who focuses on studies of High energy collisions in the Large Hadron Collider through which he explores supersymmetry and the mechanism of spontaneous symmetry breaking. He is a senior scientist at CERN and professor of physics at the National and Kapodistrian University of Athens. He was elected a Fellow of the Royal Society (FRS) in 2019.
Christopher Scott Hill is an American particle physicist and Professor of Physics at The Ohio State University. He is known for his contributions to the study of the top quark and for co-founding the milliQan Experiment at the Large Hadron Collider.
