Martin Lewis Perl (June 24, 1927 – September 30, 2014) was an American
chemical engineer
In the field of engineering, a chemical engineer is a professional, equipped with the knowledge of chemical engineering, who works principally in the chemical industry to convert basic raw materials into a variety of products and deals with the ...
and
physicist
A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe.
Physicists generally are interested in the root or ultimate caus ...
who won the
Nobel Prize in Physics
)
, image = Nobel Prize.png
, alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then " ...
in 1995 for his
discovery
Discovery may refer to:
* Discovery (observation), observing or finding something unknown
* Discovery (fiction), a character's learning something unknown
* Discovery (law), a process in courts of law relating to evidence
Discovery, The Discovery ...
of the
tau lepton
The tau (), also called the tau lepton, tau particle, tauon or tau electron, is an elementary particle similar to the electron, with negative electric charge and a spin of . Like the electron, the muon, and the three neutrinos, the tau is a l ...
.
Life and career
Perl was born in New York City, New York. His parents, Fay (née Resenthal), a secretary and bookkeeper, and Oscar Perl, a stationery salesman who founded a printing and advertising company, were
Jewish
Jews ( he, יְהוּדִים, , ) or Jewish people are an ethnoreligious group and nation originating from the Israelites Israelite origins and kingdom: "The first act in the long drama of Jewish history is the age of the Israelites""The ...
immigrants
Immigration is the international movement of people to a destination country of which they are not natives or where they do not possess citizenship in order to settle as permanent residents or naturalized citizens. Commuters, tourists, and ...
to the US from the
Polish
Polish may refer to:
* Anything from or related to Poland, a country in Europe
* Polish language
* Poles, people from Poland or of Polish descent
* Polish chicken
*Polish brothers (Mark Polish and Michael Polish, born 1970), American twin screenwr ...
area of
Russia
Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
.
Perl is a 1948
chemical engineering
Chemical engineering is an engineering field which deals with the study of operation and design of chemical plants as well as methods of improving production. Chemical engineers develop economical commercial processes to convert raw materials int ...
graduate of Brooklyn Polytechnic Institute (now known as
NYU-Tandon) in Brooklyn. After graduation, Perl worked for the
General Electric Company
The General Electric Company (GEC) was a major British industrial conglomerate involved in consumer and defence electronics, communications, and engineering. The company was founded in 1886, was Britain's largest private employer with over 250 ...
, as a chemical engineer in a factory producing electron vacuum tubes. To learn about how the electron tubes worked, Perl signed up for courses in atomic physics and advanced calculus at
Union College
Union College is a private liberal arts college in Schenectady, New York. Founded in 1795, it was the first institution of higher learning chartered by the New York State Board of Regents, and second in the state of New York, after Columbia Co ...
in
Schenectady, New York
Schenectady () is a city in Schenectady County, New York, United States, of which it is the county seat. As of the 2020 census, the city's population of 67,047 made it the state's ninth-largest city by population. The city is in eastern New Y ...
, which led to his growing interest in physics, and eventually to becoming a graduate student in physics in 1950.
He received his Ph.D. from
Columbia University
Columbia University (also known as Columbia, and officially as Columbia University in the City of New York) is a private research university in New York City. Established in 1754 as King's College on the grounds of Trinity Church in Manhatt ...
in 1955, where his thesis advisor was
I.I. Rabi
Isidor Isaac Rabi (; born Israel Isaac Rabi, July 29, 1898 – January 11, 1988) was an American physicist who won the Nobel Prize in Physics in 1944 for his discovery of nuclear magnetic resonance, which is used in magnetic resonance ima ...
. Perl's thesis described measurements of the nuclear quadrupole moment of
sodium
Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable iso ...
, using the atomic beam resonance method that Rabi had won the Nobel Prize in Physics for in 1944.
Following his Ph.D., Perl spent 8 years at the
University of Michigan
, mottoeng = "Arts, Knowledge, Truth"
, former_names = Catholepistemiad, or University of Michigania (1817–1821)
, budget = $10.3 billion (2021)
, endowment = $17 billion (2021)As o ...
, where he worked on the physics of
strong interaction
The strong interaction or strong force is a fundamental interaction that confines quarks into proton, neutron, and other hadron particles. The strong interaction also binds neutrons and protons to create atomic nuclei, where it is called the n ...
s, using
bubble chamber
A bubble chamber is a vessel filled with a superheated transparent liquid (most often liquid hydrogen) used to detect electrically charged particles moving through it. It was invented in 1952 by Donald A. Glaser, for which he was awarded the 196 ...
s and
spark chamber {{short description, Charged particle detector
A spark chamber is a particle detector: a device used in particle physics for detecting electrically charged particles. They were most widely used as research tools from the 1930s to the 1960s and have ...
s to study the scattering of
pion
In particle physics, a pion (or a pi meson, denoted with the Greek letter pi: ) is any of three subatomic particles: , , and . Each pion consists of a quark and an antiquark and is therefore a meson. Pions are the lightest mesons and, more gene ...
s and later
neutron
The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons beh ...
s on
proton
A proton is a stable subatomic particle, symbol , H+, or 1H+ with a positive electric charge of +1 ''e'' elementary charge. Its mass is slightly less than that of a neutron and 1,836 times the mass of an electron (the proton–electron mass ...
s.
While at Michigan, Perl and
Lawrence W. Jones
Lawrence William Jones (born 1925) is an American academic and professor emeritus in the Physics Department at the University of Michigan. His field of interest is high energy particle physics.
Early life and education
Lawrence W. Jones was ...
served as co-advisors to
Samuel C. C. Ting
Samuel Chao Chung Ting (, born January 27, 1936) is a Chinese-American physicist who, with Burton Richter, received the Nobel Prize in 1976 for discovering the subatomic J/ψ particle. More recently he has been the principal investigator in res ...
, who earned the Nobel Prize in Physics in 1976.
Seeking a simpler interaction mechanism to study, Perl started to consider
electron
The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family,
and are generally thought to be elementary particles because they have no kn ...
and
muon
A muon ( ; from the Greek letter mu (μ) used to represent it) is an elementary particle similar to the electron, with an electric charge of −1 '' e'' and a spin of , but with a much greater mass. It is classified as a lepton. As wi ...
interactions.
He had the opportunity to start planning experimental work in this area when he moved in 1963 to the
Stanford Linear Accelerator Center
SLAC National Accelerator Laboratory, originally named the Stanford Linear Accelerator Center,
is a United States Department of Energy National Laboratory operated by Stanford University under the programmatic direction of the U.S. Departme ...
(SLAC), then being built in
California
California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...
. He was particularly interested in understanding the
muon
A muon ( ; from the Greek letter mu (μ) used to represent it) is an elementary particle similar to the electron, with an electric charge of −1 '' e'' and a spin of , but with a much greater mass. It is classified as a lepton. As wi ...
: why it should interact almost exactly like the electron but be 206.8 times heavier, and why it should decay through the route that it does. Perl chose to look for answers to these questions in experiments on high-energy charged
lepton
In particle physics, a lepton is an elementary particle of half-integer spin ( spin ) that does not undergo strong interactions. Two main classes of leptons exist: charged leptons (also known as the electron-like leptons or muons), and neutr ...
s. In addition, he considered the possibility of finding a third
generation
A generation refers to all of the people born and living at about the same time, regarded collectively. It can also be described as, "the average period, generally considered to be about 20–30 years, during which children are born and gr ...
of lepton through electron-
positron
The positron or antielectron is the antiparticle or the antimatter counterpart of the electron. It has an electric charge of +1 '' e'', a spin of 1/2 (the same as the electron), and the same mass as an electron. When a positron collides ...
collisions.
Perl is one of the 20 American recipients of the Nobel Prize in Physics to sign a letter addressed to President
George W. Bush
George Walker Bush (born July 6, 1946) is an American politician who served as the 43rd president of the United States from 2001 to 2009. A member of the Republican Party, Bush family, and son of the 41st president George H. W. Bush, he ...
in May 2008, urging him to "reverse the damage done to basic science research in the Fiscal Year 2008 Omnibus Appropriations Bill" by requesting additional emergency funding for the
Department of Energy A Ministry of Energy or Department of Energy is a government department in some countries that typically oversees the production of fuel and electricity; in the United States, however, it manages nuclear weapons development and conducts energy-rel ...
's
Office of Science
The Office of Science is a component of the United States Department of Energy (DOE). The Office of Science is the lead federal agency supporting fundamental scientific research for energy and the Nation’s largest supporter of basic research in t ...
, the
National Science Foundation
The National Science Foundation (NSF) is an independent agency of the United States government that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National I ...
, and the
National Institute of Standards and Technology
The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical sci ...
.
He died after a heart attack
at Stanford University Hospital on September 30, 2014 at the age of 87. His son,
Jed Perl
Jed Perl (born 1951) is an American art critic and author in New York City. He was a longtime staff of ''The New Republic''.
Career
Jed Perl initially trained as a painter. He holds a Bachelor of Arts from Columbia College and also studied at th ...
, is an author and art critic for ''
The New Republic
''The New Republic'' is an American magazine of commentary on politics, contemporary culture, and the arts. Founded in 1914 by several leaders of the progressive movement, it attempted to find a balance between "a liberalism centered in hum ...
''.
Discovery of the tau particle
The
tau
Tau (uppercase Τ, lowercase τ, or \boldsymbol\tau; el, ταυ ) is the 19th letter of the Greek alphabet, representing the voiceless dental or alveolar plosive . In the system of Greek numerals, it has a value of 300.
The name in English ...
lepton (τ, also called the tau particle, tauon or simply tau) is an
elementary particle
In particle physics, an elementary particle or fundamental particle is a subatomic particle that is not composed of other particles. Particles currently thought to be elementary include electrons, the fundamental fermions ( quarks, leptons, an ...
similar to the electron, with negative
electric charge
Electric charge is the physical property of matter that causes charged matter to experience a force when placed in an electromagnetic field. Electric charge can be ''positive'' or ''negative'' (commonly carried by protons and electrons respe ...
and a
spin of , but with 3477 times the mass. Together with the
electron
The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family,
and are generally thought to be elementary particles because they have no kn ...
, the
muon
A muon ( ; from the Greek letter mu (μ) used to represent it) is an elementary particle similar to the electron, with an electric charge of −1 '' e'' and a spin of , but with a much greater mass. It is classified as a lepton. As wi ...
, and the three
neutrino
A neutrino ( ; denoted by the Greek letter ) is a fermion (an elementary particle with spin of ) that interacts only via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass ...
s, it is classified as a
lepton
In particle physics, a lepton is an elementary particle of half-integer spin ( spin ) that does not undergo strong interactions. Two main classes of leptons exist: charged leptons (also known as the electron-like leptons or muons), and neutr ...
.
The tau was first detected in a series of experiments between 1974 and 1977 by Perl with his colleagues at the
SLAC
SLAC National Accelerator Laboratory, originally named the Stanford Linear Accelerator Center,
is a United States Department of Energy National Laboratory operated by Stanford University under the programmatic direction of the U.S. Departm ...
-
LBL group.
[
] Their equipment consisted of
SLAC
SLAC National Accelerator Laboratory, originally named the Stanford Linear Accelerator Center,
is a United States Department of Energy National Laboratory operated by Stanford University under the programmatic direction of the U.S. Departm ...
's then-new – colliding ring, called
SPEAR
A spear is a pole weapon consisting of a shaft, usually of wood, with a pointed head. The head may be simply the sharpened end of the shaft itself, as is the case with fire hardened spears, or it may be made of a more durable material fasten ...
, and the
LBL magnetic detector. They could detect and distinguish between leptons, hadrons and
photon
A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless, so they always ...
s. SPEAR was able to collide electrons and positrons at higher energies than had previously been possible, initially at up to 4.8 GeV and eventually at 8 GeV, energies high enough to lead to the production of a tau/antitau pair.
The tau has a lifetime of only and so these particles decayed within a few millimetres of the collision.
Hence Perl and his coworkers did not detect the tau directly, but rather discovered anomalous events where they detected either an electron and a muon, or a positron and an antimuon:
The need for at least two undetected particles was shown by the inability to conserve energy and momentum with only one. However, no other muons, electrons, photons, or hadrons were detected. It was proposed that this event was the production and subsequent decay of a new particle pair:
: + → + → + + 4
This was difficult to verify, because the energy to produce the pair is similar to the threshold for
D meson
The D mesons are the lightest particle containing charm quarks. They are often studied to gain knowledge on the weak interaction. The strange D mesons (Ds) were called "F mesons" prior to 1986.
Overview
The D mesons were discovere ...
production. Work done at
DESY
The Deutsches Elektronen-Synchrotron (English ''German Electron Synchrotron''), commonly referred to by the abbreviation DESY, is a national research center in Germany. It operates particle accelerators used to investigate the structure of matt ...
-Hamburg, and with the Direct Electron Counter (DELCO) at
SPEAR
A spear is a pole weapon consisting of a shaft, usually of wood, with a pointed head. The head may be simply the sharpened end of the shaft itself, as is the case with fire hardened spears, or it may be made of a more durable material fasten ...
, subsequently established the mass and spin of the tau.
The symbol τ was derived from the Greek ''τρίτον'' (''triton'', meaning "third" in English), since it was the third charged lepton discovered.
Nobel Prize and later career
Perl won the Nobel Prize in 1995 jointly with
Frederick Reines
Frederick Reines ( ; March 16, 1918 – August 26, 1998) was an American physicist. He was awarded the 1995 Nobel Prize in Physics for his co-detection of the neutrino with Clyde Cowan in the neutrino experiment. He may be the only scientist in ...
. The prize was awarded "for pioneering experimental contributions to lepton physics". Perl received half "for the discovery of the tau lepton" while Reines received his share "for the detection of the
neutrino
A neutrino ( ; denoted by the Greek letter ) is a fermion (an elementary particle with spin of ) that interacts only via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass ...
".
In 1996 he published ''Reflections on Experimental Science'', which consists of "comments, scientific reprints, reflections, and a memoir ...".
He joined
University of Liverpool
, mottoeng = These days of peace foster learning
, established = 1881 – University College Liverpool1884 – affiliated to the federal Victoria Universityhttp://www.legislation.gov.uk/ukla/2004/4 University of Manchester Act 200 ...
as a visiting professor. He served on the board of advisors of
Scientists and Engineers for America
Scientists and Engineers for America (SEA) was an organization focused on promoting sound science in American government, and supporting candidates who understand science and its applications. SEA was formed on September 27, 2006, and describes it ...
, an organization focused on promoting sound science in American government. In 1996, he received the Golden Plate Award of the
American Academy of Achievement
The American Academy of Achievement, colloquially known as the Academy of Achievement, is a non-profit educational organization that recognizes some of the highest achieving individuals in diverse fields and gives them the opportunity to meet o ...
. In 2009, Perl received an honorary doctorate from the
University of Belgrade
The University of Belgrade ( sr, / ) is a public university in Serbia. It is the oldest and largest modern university in Serbia.
Founded in 1808 as the Belgrade Higher School in revolutionary Serbia, by 1838 it merged with the Kragujevac-b ...
.
See also
*
List of Jewish Nobel laureates
Nobel Prizes have been awarded to over 900 individuals, of whom at least 20% were Jews.
*
*
*
*
*
*
*
*
The number of Jews receiving Nobel prizes has been the subject of some attention.*
*
*"Jews rank high among winners of Nobel, but why ...
References
External links
*
* including the Nobel Lecture, December 8, 1995 ''Reflections on the Discovery of the Tau Lepton''
Nobel Prize press release, explaining the significance of Perl's workPersonal blog: Reflections on PhysicsUniversal fluid droplet ejector (Martin Lewis Perl)
Two-dimensional fluid droplet arrays generated using a single nozzle (Martin Lewis Perl)
Gary Feldman, John Jaros, and Rafe H. Schindler, "Martin L. Perl", Biographical Memoirs of the National Academy of Sciences (2016)
{{DEFAULTSORT:Perl, Martin Lewis
1927 births
Nobel laureates in Physics
American Nobel laureates
American chemical engineers
American people of Belarusian-Jewish descent
American physicists
Columbia University alumni
Jewish American scientists
Jewish physicists
2014 deaths
Members of the United States National Academy of Sciences
Particle physicists
United States Merchant Marine Academy alumni
University of Michigan faculty
Wolf Prize in Physics laureates
Polytechnic Institute of New York University alumni