J3 HL Quarks

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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