Martin L. Perl et al- The Search for Fractional Charge Particles and Very Massive Particles in Bulk Matter

8/3/2019 Martin L. Perl et al- The Search for Fractional Charge Particles and Very Massive Particles in Bulk Matter

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Martin L. Perl, Valerie Halyo, Peter C. Kim,

Eric R. Lee, Irwin T. Lee, and Dinesh Loomba

Stanford Linear Accelerator Center

Stanford University

Stanford, CA 94306

THE SEARCH FOR

FRACTIONAL CHARGE PARTICLES

AND

VERY MASSIVE PARTICLES

IN

BULK MATTER


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Part 1

FREE FRACTIONAL CHARGE

ELEMENTARY PARTICLES

fUse to denote a fractional charge particle


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SEARCH METHODS FOR

FREE FRACTIONAL CHARGE


FFFFCosmic Rays :

FFBulk Matter :

FFFF Accelerators: Straightforward butlimited in mass anduncertain in productioncross section.

Worth trying but

limited in mass and

uncertain in production

process.

General method,

dependent upon productionin early universe. Very

large mass range. Our

preference.


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FROM EARLY UNIVERSE TO

SOLAR SYSTEM

space

solar system

early universe

star

f

f f

f

f

f f

f

fX

f fY


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FRACTIONAL CHARGE PARTICLES

CHANGE THE CHEMISTRY OF

ATOMS AND MOLECULES

For example, a hydrogen atom with an

additional +1/3 f attached to the nucleushas chemical properties similar to fluorine.

It is similar to a helium atom with a -1/3 f in

a close orbit.*

Therefore the significance of searches in

bulk matter depends upon the chemical and

refining processing history of the material,

including geochemical processes.

*K. S. Lackner and G. Zweig, Phys. Rev. D 28, 1671 (1983);

K. S. Lackner and G. Zweig, Novel Results in Particle Physics

(Am. Inst. Phys., New York,1982)


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FFFFEarth: Accessible now but geochemical

processing must be considered.

Some ancient minerals of great

interest.

FF

Meteorites from asteroids : Great interest

because come from mostprimitive material in solar system.

FF Moon : Some special interest butsamples scarce.

WHERE TO SEARCH FOR

FRACTIONAL CHARGE PARTICLESIN SOLAR SYSTEM

FFFFAsteroids: Best search material, either

bring back large samples or

carry out searches on asteroid.


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SEARCH METHODS IN

BULK MATTER

FFFFLiquid Drop: The method we use; based

on the original Millikan oil

drop method. The material

may be a liquid, a solution,

or a suspension of

a mineral or otherpowder in a liquid. Will

describe next.

FFFF

Levitometer: Suspend a ball of

material usingferromagnetism or

superconductivity. Measure

charge by oscillation in

electric field.


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OUR ORIGINAL

LIQUID DROP METHOD

Drop

generator

Falling drop already

measured

Falling drop just

produced

Trajectory of falling

drop being

measured

Upper electric

plate

Lower electric

plate

Stroboscopic light

source, flashes att intervals.

Vertical E field

alternating in

direction

Lens

CCD face of

video camera.

Area of CCD

sets field of

view of drops

Image of

trajectory of

falling drop

.

Use drops with diameters from 5 to 15 m

Once drop generator is set, diameter is constant to 0.1 %


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PHYSICS OF ORIGINAL

LIQUID DROP METHOD

Force=6rVterm

Stokes Law

Vterm = terminal velocity =viscosity of air

r = radius of drop


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We determine q and m from:

mg +qE down= 6 rVterm,down

mg - qEup = 6 rVterm,up

r = drop radius

q =drop electric charge

g = acceleration of gravity

Eup = electric field when pointed up

Edown

= electric field when pointed u


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PUBLISHED RESULTS OF

LEVITOMETER AND

LIQUID DROP SEARCHESIN BULK MATTER

Method Experiment Material Sample

Mass (mg)

superconducting LaRue et al. niobium 1.1

levitometer

Marinelliet al. iron 3.7

ferromagnetic Smith et al. niobium 4.9

levitometerJones et al. meteorite 2.8

Joyce et al. sea water 0.05

liquid drop Savage et al. mercury 2.0

Maret al. silicone oil 1.1

No fractional charges claimed except by LaRue et al. Their

claim NOT confirmed by Smith et al.

1 mg = 6_1020 nucleons


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OUR NEW UNPUBLISHED

SEARCH IN SILICONE OIL

We have just concluded a search through

17 mg of silicone oil. This used 4.1_107

drops of about 10 mm diameter. The charge

of each drop was measured with a precisionof 1/40 of an electron charge.

We found no evidence for fractional charge

particles but there is a data point thatargues for repeating the experiment with a

larger sample.

For details see:

V. Halyo et al., SLAC-PUB-8283Submitted to Phys.Rev.Lett.

e-Print Archive: hep-ex/9910064


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COMMENTS ON THESE SEARCHES

AND NEXT SEARCHES

$$$$The silicone oil results will be repeated

with a larger sample.

$$ But the major next step is to studyunrefined materials particularly

meteorites. We have samples of theAllende meteorite.

$$ We will also study fluoraptite, amineral that collects fluorine-like

elements.

$$ Sample sizes will be increased.


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Dropgenerator

Vertical electric

plates giving

horizontal electric

field, E

Laminar air flow to reduce

vertical terminal velocity

of large drops so that they

remain in the measuring

region

OUR NEW

HORIZONTAL ELECTRIC FIELDLIQUID DROP METHOD

Uses much larger drops: 20 to 100 m diameter

qE = 6rVterm,horizontal


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%%%% Increase sample sizes fromtens of milligrams to tens

of grams or even a kilogram.

%%%% Bring large samples from

asteroids or put searchapparatus on asteroid.

TWENTY FIVE YEAR GOALS FOR

FRACTIONAL CHARGE PARTICLESEARCH


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Part 2

VERY MASSIVE AND STABLE


Consider very massive particle:

tttt produced in early universe,

tttt stable,

tttt charged or bound to charged particle, and

tttt present in solar system.


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LIQUID DROP SEARCH METHOD

FORVERY MASSIVE PARTICLES

1 GeV/c2 = 1.8 10-24 grams

Mass of 5 m diameter drop = 10-10 grams

therefore

Mass of 5 m diameter drop is about

5 1013 GeV/c2


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Force=6rVterm

Stokes Law again:


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Drop of mass m falling in air:

Vterm(m) = mg/(6r

Drop of mass m falling containingan elementary particle of mass M

falling in air:

Vterm

(m+M) = (m+M)g/(6r)


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v

v(m) v(m+M)

logdN/dV

falling dropbeing measured

stroboscopic

light source

CCD face of video

camera used to

measure terminal

velocity and drop

radius via imaging

drop

imaginglens

drop generator


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The lower mass search limit is set by the

mass of the smallest mass drops that can

be used in a practical search and by the

extent of the tails on the v(m) peak.

The lower mass search limit is between

1013 and 1014 GeV/c2

LOWER MASS LIMIT ON SEARCH



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UPPER MASS LIMIT ON SEARCH


The upper mass search limit is set by the

requirement that the massive particle beheld in ordinary matter by the Coulomb

force Fc between the particles charge

and the nearby atoms. Estimate

Fc = 1 eV/10-10 m = 1.6_10-9nt

On the Earths surface require: Mg < Fc.

Therefore the upper mass limit on the

Earth is:

M < 1.6_10-10kg = 1017 GeV/c2


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SEARCHING FOR VERY MASSIVE

PARTICLES IN METEORITES

$$$$ Searching for very massive particlesin terrestrial minerals is chancy

because of the geological history of

the earth.

$$$$ The best materials for very massiveparticle searches are meteorites. We

have samples of the Allende meteorite.

$$$$ But there is a problem with the uppermass limit when searching in

meteorites. When meteorites enter the

atmosphere and slow down the

deceleration force may be 100g to

1000g. Therefore the more massive

particles will not stay in the meteorite.


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%%%% Develop experimental

method by searching inmeteorites and other

minerals on Earth.

%%%% Send the search apparatusto an asteroid and search

on the asteroid. There are

many advantages includinga larger search range since

gasteroid

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Martin L. Perl et al- The Search for Fractional Charge Particles and Very Massive Particles in Bulk Matter