give explanations if you can, thank you so much!
- Exploring The Quark Model Please Help As Soon As Possible And Give Explanations If You Can Thank You So Much 1 (149.02 KiB) Viewed 40 times
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Leptors Leptons Letters SMA Deve Wa tu Some Subnuclear Particies *. i ATLEA TEMPI PART ATUNE 24 Some Subnuclear Particles Windy Ton Am in 12.12 Dezm Some Subnuclear Particles 1 203 ADA LUMI V ATA JUT 2486 How Men 725 7777 Summary of basic quark properties Quark flavor Charge Strangeness up (u) +2/3 0 down (d) - 1/3 0 strange (s) 1/3 anti-up (ū) 2/3 0 - anti-down (d) + 1/3 0 anti-strange (5) +1/3 +1 4) Particles of the baryon family are always made of three quarks. Antibaryons are made of three antiquarks. Never two or four - always three, and quarks never mix with antiquarks in these families. The red box shows the baryons and anti-baryons on the Particle Chart. 5) Particles in the meson family do mix quarks with antiquarks. Mesons are always made of just two quarks - one 'regular' quark and one antiquark. 6) Particles in the lepton family - this includes the electron family and the muon family - are free, independent particles and are not made of quarks at all. C.5 20N then pom af 14-90 12.1² 1.2. 17.12 17-12 13. Iv 2 17.1. 17.4. 11 17-12- 1.2
Read slowly and carefully through these examples to see how the quark model rules work together. Example 1 - what quarks make up a neutron? Find the neutron on the Particle Chart; you'll see that it is in the baryon family. Rule 4, above, tells us that a neutron must be made of three quarks, but which ones? Check the strangeness of the neutron; you'll see it equals zero. (A neutron may be weird, but it's not strange! Ba-dum-ching!) That means that only u and d quarks are involved, and the total charge must add to zero. The only way to make that work requires one u quark (with a +2/3 charge, remember) and two d quarks (-1/3 each). So, a neutron can be expressed as udd. (You could write the quarks in any order, but for consistent clarity write the u quarks first, then the d's and last, if any, the s's.) To recap: first find the family to which the particle in question belongs, and use rules 4, 5, and 6 to determine how many quarks - if any- make up the particle. Then check the strangeness (rule 3) to determine how many s or anti-s quarks, if any, are present. Last, check the charge to see how many other quarks are needed to add together to make up the total charge. Example 2 - what quarks make up the antisigma minus? Check the chart to find that its charge is, of course, -1 (the word minus tells us that) and its strangeness lists as +1. Start from that strangeness: the particle must contain one s quark (rule 3, above). Since the 5 conveys a charge of +1/3, we need two other antiquarks (rule 4) to make a total charge of -1. That can be accomplished only with two ū quarks, so we have the answer! The anti-sigma minus can be written as ū ū š. Do you see? Example 3 - what quarks are found in the K minus particle? You'll find that at the lower left of the particle chart, in the meson family. Rule 5 tells us that mesons are simple particles, made of one quark and one anti-quark. You'll see that the K minus has a charge of -1, of course, and a strangeness of -1 as well. That value of strangeness means that the particle contains one s quark, conveying a charge of -1/3. We need one antiquark in the combo, and to make a charge of -1 it must be a ū. The K minus, then, is really us. Example 4-how about the muon? You will find it in the left column, among the other leptons. Rule 6, you recall, says that leptons appear to be separate, basic particles not made of quarks, so this is a trick question! There are no quarks of any kind, the model says, in a lepton. One more example: Example 5 - What would you call a particle made of one u quark and two s quarks, or uss? As if you were a detective, gather evidence. Start from the count of quarks: since we have three regular, non-antiquarks, we must have a baryon (rule 4). Next, check the count of s quarks. Since we have two, the strangeness of this example particle equals -2. Finally check its charge; one u gives +2/3, and each s takes away 1/3 (that is, the charge of each equals -1/3), leaving us with a charge of zero. We have a neutral baryon with strangeness of -2, and we have found the identity of our suspect - the xi zero.
What you'll need: What you'll do: Go over the rules and examples as often as necessary to understand them well. Particle Chart from Learn and the rules of the quark model, above For the first twelve particles on the Report Sheet, type as many x characters as needed for each kind of quark in that particle. In case you find a trick question, as in Example 4, put your x in the last box, Not made of quarks. See the example on the Report Sheet. For the last eight entries on the Report Sheet, type the name of the particle from the list of particles that has that quark configuration, as in Example 5. Remember, all you need to know you will find in rules 1 through 6, above. Do you get the feeling that this is all made up? I hope so - because it was all made up! All science in an early stage is made up, as people struggle to find patterns in the world. The quark model works - that is, its predictions correspond with nature - so we accept it as valid. New particles have been discovered, leading to postulating new kinds of quarks, as you saw in class. So far, every known particle can be described in terms of the new, fully developed quark model, a remarkable success.
Leptons Photon Family Photon 7 0 1 Electron Family Electron e™ 0.5 Positron e+ Electron's neutrino Electron's antineutrino v Muon Family Mu minus u- Mu plus u* 106 Muon's neutrino 2₂ 0 Muon's antineutrino 0 TT 135 0 + 140 0 T 140 0 K+ 494 0 K- 494 0 K° 498 0 K 498 O 7° 549 O Meson Family Pi zero Pi plus Pi minus Kay plus Kay minus Kay zero Antikay zero Eta Mass (MeV) Symbol Spin (Units of h/2m) Family Number Charge (Units of lel) Strangeness Lifetime (seconds) 200 0.5 } } 106 1/ Some Subnuclear Particles Baryon Family Proton Antiproton Neutron Antineutron Lambda Antilambda Sigma plus Antisigma, minus Sigma zero Antisigma, zero Sigma minus Antisigma, plus Xi zero Antixi zero Xi minus Antixi, plus Omega minus Antiomega, plus 00 Stable +1 -1 0 Stable -1 +1 0 Stable 0 0 Stable -1 0 Stable +1 -1 2.2 x 10-6 2.2 x 10- Stable Stable 0.8 x 10-16 2.6 × 10-B 2.6 x 10-8 1.2 × 10~9 1.2 x 10-8 (0.9 x 10-10 5.4 x 10-8 2×10-19 +1 FTFT -1 +1 +1 ī+°° -1 °FTFT 0 +1 -1 OOOO 0 0 0 0 0 ܘ ܕ 0 0 +1 +1 0 +11 0-1) 0 0 Spin (Units of h/2T) Mass (MeV) Symbol Family Number Charge (Units of lel) Strangeness Lifetime (seconds) dih zोटे ददि P+ 938 // P- 938 N° 940 No 940 / A 1116 1116 / Σ+ 1189 - 1189 Σ 1192 } º 1192 Σ- 1197 A + 1197 // 핑 1315 3 1315 E- 1321 / + 1321 - 1673 + +1673 +1 0 -1 -1 0 +1 0 0 -1 0 0 0 -1 +1 -1 0 +1 +1 +1 +1 -1 -1 -1 +1 +1 0 -1 0 +1 +1 -1 -1 -1 +1 +1 +1 0-2 0 +2 +1 -1 -2 -1 +1 +2 +1 -1 -3 -1 +1 +3 Stable Stable 10³ 10³ 2.5 × 10-¹0 2.5 × 10-¹0 0.8 × 10-¹0 0.8 x 10-10 <10-¹4 <10-¹4 1.5 X 10-¹0 1.5 X 10-¹0 3 x 10-10 3 x 10-20 1.7 x 10-10 1.7 X 10-¹0 1.3 X 10-10 1.3 x 10-¹0
Ideas at Work Module 7 Report Sheet Exploring the quark model Name For each of these subatomic particles, enter an x in the box below each type of quark present in it. Use multiple x's to indicate multiple quarks of that type. Be careful, because two of the particles are leptons that are not made of quarks. In those cases, enter an x in the 'Not made of quarks' box. Example 1 p+ udsuds Not made of quarks proton vv x XX X A proton is a baryon, so it must be made of three quarks. Its charge of +1 can only be realized with two up quarks (+2/3 each) and one down quark (-1/3). No strange quarks are involved because the strangeness of the proton is zero. Example 2 Ko udsuds Not made of quarks kay zero ×× X X Find Kº on the particle chart in the meson family, so it must contain one quark and one antiquark. Its strangeness of +1 is key: that means it must contain one anti-s quark with a +1/3 charge. Since the overall charge is zero, add a down quark with its -1/3 charge. 1) Nº udsuds Not made of quarks neutron 2) μ* udsuds Not made of quarks mu plus 3) + udsuds Not made of quarks sigma plus 4) TC udsuds Not made of quarks pi minus
5) udsuds Not made of quarks xi zero 6) udsuds Not made of quarks antixi zero 7) Kº udsuds Not made of quarks antikay zero 8) De udsuds Not made of quarks electron neutrino 9) Ao udsuds Not made of quarks lambda zero (The particle chart just says lambda) - 10) udsud s Not made of quarks antisigma minus 11) TC + udsuds Not made of quarks pi plus udsuds Not made of quarks 12) - sigma minus Which particle would each of these quark configurations represent? Name the specific particle, not just the family name. 13) dss 14) us 15) uud 16) dds 17) ud 18) us 19) uss 20) sss