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Option J: Particle physics
J3 Quarks
This part of Option J has already been covered in
Option D5 Quarks.
It is replicated here without any changes.
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J.3.1 List the six types of quark.J.3.2 State the content, in terms of quarks and
antiquarks, of hadrons (that is, baryons and
mesons.
J.3.3 State the quark content of the proton and
the neutron.J.3.! "efine baryon number and app#y the
conser$ation of baryon number.
J.3.% "educe the spin structure of hadrons (that
is, baryons and mesons. &n#y an e#ementary
discussion in terms of 'spin up and 'spindo)n is required. See ".!.! abo$e for
detai#s.
Option J: Particle physics
J3 Quarks
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List the six types of quark.*ou ha$e a#ready been introduced to the six
quarks+
Quarks participate in the stron force )hose
carrier is the #uon.
Option J: Particle physics
J3 Quarks
Quark
Flavor Symbol Charge
Up u + 2!
"o#n $ % &!
Strange s % &!
Charm c + 2!
'ottom b % &!
(op t + 2!
)nti*uark
Symbol Charge
u % 2!
$ + &!
s + &!
c % 2!
b + &!
t % 2!
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State the content, in terms of quarks andantiquarks, of hadrons (that is, baryons and
mesons.
- ha$ronis a partic#e that participates in the
stron force.
Since quarks participate in the stron force, andsince baryons and mesons are made of quarks,
baryons and mesons are hadrons.
-baryonis made of three quarks (qqq. -n
antibaryon is made of three antiquarks (qqq.
-mesonis made up of a quark and an antiquark(qq+
Option J: Particle physics
J3 Quarks
FYI
- singlequark cannot be iso#ated. e )i## ta#k
about quark confineent#ater. /asica##y,
confinement states that you cannot separate asin#e quark from a hadron.
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State the quark content of the proton and theneutron.
- proton is a baryon made up of t)o up quarks and
a do)n quark.p0 (uud.
- neutron is a baryon made up of one up quark and
t)o do)n quarks. n0 (udd.
Option J: Particle physics
J3 Quarks
-4L+
Sho) that the chare of a proton is 51, and that
the chare of a neutron is 6.
S&L789&:+
8he chare of an up quark is 52;3.
8he chare of a do)n quark is
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"efine baryon number and app#y the conser$ationof baryon number.
8he baryon number of a quark is 51;3. 8he baryon
number of an antiquark is 89>+ hat is the baryon number of a proton
and an antiproton?
S&L789&:+
4roton 0 uud + 51;3 5 51;3 5 51;3 0 51.
-ntiproton 0 uud +
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"educe the spin structure of hadrons (that is,baryons and mesons.
8he spin of a quark (or antiquark is spin up(
0 1;2 or spin $o#n(0 + "educe the possib#e spin structures of
a baryon+
S&L789&:+ - baryon is (qqq+
4ossibi#ity 1+ 51;2 5 51;2 5 51;2 0 53;2.
4ossibi#ity 2+ 51;2 5 51;2 5
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"educe the spin structure of hadrons (that is,baryons and mesons.
8he spin of a quark (or antiquark is spin up(
0 1;2 or spin $o#n(0 + "educe the possib#e spin structures of
a meson+
S&L789&:+ - meson is (qq+
4ossibi#ity 1+ 51;2 5 51;2 0 51.
4ossibi#ity 2+ 51;2 5
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"educe the spin structure of hadrons (that is,baryons and mesons.
Option J: Particle physics
J3 Quarks
Pauli says they can,t have i$entical
*uantum numbers- (heir colors $ier-
) proton has a *uark structure o uu$-
.ach *uark has a spin o /-
0 t#o o the three *uarks has a spin o
+ / an$ the other a spin o 1 / the proton
has a spin o /-
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J.3.A xp#ain the need for co#or in forminbound states of quarks.
J.3.B State the co#or of quarks and #uons.
J.3.C &ut#ine the concept of straneness.
J.3.D "iscuss quark confinement.
J.3.16 "iscuss the interaction that bindsnuc#eons in terms of the co#or force bet)een
quarks.
Option J: Particle physics
J3 Quarks
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xp#ain the need for co#or in formin boundstates of quarks.
8)o e#ectrons repe#, yet an e#ectron and a
positron (or proton attract. 8o exp#ain such
interactions )e use the mode# of Echare,F and
i$e chares either a (5 or a (G $a#ue.Quarks, on the other hand, seem to sho) three
types of chare, rather than t)o. - mode# usin
(5 and (
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State the co#or of quarks and #uons.Just as (5 and (
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State the co#or of quarks and #uons.I#uons, the stron force carrier, ha$e t)o co#ors
and are not )hite (and thus ha$e a non
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&ut#ine the concept of straneness.8he straneness number !of a baryon is re#ated
to the number of strane quarks the partic#e has
and is found usin the formu#a
Option J: Particle physics
J3 Quarks
strangeness S!0 -ntistrane quarks
< strane quarks
-4L+ 8he #ambda Hero partic#e (6 is a
baryon ha$in the quark combo of (uds. hat is
its chare? hat is its straneness?
S&L789&:+
Krom a pre$ious tab#e the chares are u 0 52;3,
d 0
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&ut#ine the concept of straneness.
Option J: Particle physics
J3 Quarks
(he 1is a ha$ron because it is compose$
o *uarks-
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&ut#ine the concept of straneness.
Option J: Particle physics
J3 Quarks
(he proton is compose$ o uu$-
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&ut#ine the concept of straneness.
Option J: Particle physics
J3 Quarks
0 is sss3 then the reaction can be
#ritten in terms o *uarks as ollo#s:
su + uu$ $s + us + sss(he let has an s3 u3 an$ $ let-
(he right also has an s3 u3 an$ $ let-(he *uarks are balance$ on each si$e-
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"iscuss quark confinement.Quark confinement means
that )e cannot e$er
separate a sin#e quark
from a baryon or a
meson./ecause of the nature
of the stron force
ho#din the quarks
toether )e need to
pro$ide an enery that
is proportiona# to the
separation.
$entua##y, that enery is so $ast that a ne)
quark
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"iscuss quark confinement.
Option J: Particle physics
J3 Quarks
Origin
al
meson
4e#l
y%cr
eate$
meso
n
Quar
k%
anti
*uar
kpa
ir
create$
+ro
m
energy
nee$e$
+or
sepa
ration
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"iscuss the interaction that binds nuc#eons interms of the co#or force bet)een quarks.
8he residua# co#or force of the #uons that ho#d
the quarks toether is )hat is kno)n as the
stron force.
8hus nuc#earreactors and
bombs represent
on#y the
residua# enery
in the #uon
interaction
bet)een quarks.
Option J: Particle physics
J3 Quarks
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