Beta Decays

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Beta Decays Beta rots are proton ��  neutrons or neutron ��  proton moves include W trade and are powerless cooperation the last response is electron catch where one of the nuclear electrons covers the cores. Same framework component (basically) bit diverse kinematics the semi-exact mass equation gives a base for any A. On the off chance that mass contrast between neighbors is sufficiently vast, rot will happen P461 - rots II

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Beta Decays - Q Values Determine Q of responses by taking a gander at mass distinction (cautious about electron mass) 1 MeV more Q in EC than beta+ outflow. More stage space BUT require electron wavefunction cover with core.. P461 - rots II

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Beta+ versus Electron Capture Fewer beta+ emitters than beta-in "common" cores (yet numerous in "fake" imperative in Positron Emission Tomography - PET) now and then both beta+ and EC for same cores. Diverse widths now and then just EC permitted monoenergetic neutrino. E=.87 MeV. Imperative response in the Sun. Note EC rate diverse in Sun as it is a plasma and not molecules P461 - rots II

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Beta+ versus Electron Capture from Particle Data Group P461 - rots II

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Beta Decay - 3 Body The neutrino is expected to ration rakish force (Z,A) ��  (Z+1,A) for A=even have either Z,N even-even ��  odd-odd or odd-odd ��  even-even p,n both turn 1/2 thus for even-even or odd-odd cores I=0,1,2,3… … . Be that as it may, electron has turn 1/2 I(integer) ��  I(integer) + 1/2(electron) doesn't save J require turn 1/2 neutrino. Additionally watched that electron range is consistent characteristic of >2 body rot Pauli/Fermi comprehended this in 1930s electron neutrino found 1953 (Reines and Cowan) muon neutrino found 1962 (Schwartz +Lederman/Steinberger) tau neutrino found 2000 at Fermilab P461 - rots II

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3 Body Kinematics While 3 body the cores are overwhelming and simple estimate is that electron and neutrino split accessible Q (cores has comparative force) most extreme electron vitality when E(nu)=0 illustration P461 - rots II

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Beta rot rate Start from Fermi Golden Rule first guess (Fermi). Beta=constant=strength of powerless drive Rule 1: equality of core can't change (necessary of odd*even=0) Rule 2: as antineutrino and electron are turn 1/2 they add to either 0 or 1. Gives either P461 - rots II

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Beta rot rate II Orbital rakish force concealment of 0.001 for every estimation of (in lattice component count) take a gander at thickness of states variable. Need # quantum states per vitality interim we know from quantum measurements that every molecule (very turn state) has 3 body rot yet pull back core is so overwhelming it doesn't contribute P461 - rots II

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Beta rot rate III Conservation of vitality permits one to incorporate over the neutrino (there is a delta capacity) this gives a circulation in electron force/vitality which one then coordinates over. (end point relies on upon neutrino mass) F is a capacity which relies on upon Q. It is practically loqrithmic P461 - rots II

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genuine. not "direct" because of electron mass P461 - rots II

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Beta rot rate IV FT is "just kinematics" measuring FT can contemplate atomic wavefunctions M' and quality of the frail drive at low energies bring down estimations of FT are when M' approaches 1 beta rots additionally happen for particles electron is presently relativistic and E=pc. The vital is presently simple to do. For huge particles (with rot masses little), Emax = M/2 thus rate goes as fifth force of mass P461 - rots II

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Beta rot rate V M= b M' ��  b is quality of frail collaboration. Can gauge from lifetimes of various rots trademark vitality solid vitality levels ~ 1 MeV for comparable Q, lifetimes are about P461 - rots II

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Parity Violation in Beta Decays The Parity administrator is the reflect picture and is NOT saved in Weak rots (is moderated in EM and solid) non-preservation is on the lepton side, not the atomic wave work side turn 1/2 electrons and neutrinos are (ostensibly) either right-gave (turn and force in same bearing) or left-gave (inverse) Parity changes LH to RH LH P461 - rots II

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"Handedness" of Neutrinos "handedness" is call chirality. On the off chance that the mass of a neutrino = 0 then: all neutrinos are left-given all antineutrinos are correct given Parity is maximally damaged As the mass of an electron is > 0 can have both LH and RH. Be that as it may, RH is smothered for huge vitality (as electron speed approaches c) portion RH versus LH can be dictated by explaining the Dirac condition which actually consolidates turn P461 - rots II

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Polarized Beta Decays Some cores have non-zero turn and can be enraptured by setting in an attractive field attractive snapshots of cores are little (1/M variable) thus require low temperature to have a high polarization (see Eq 14-4 and 14-5) Gamow-Teller move with S(e-nu) = 1 if Co captivated, take a gander at precise dispersion of electrons. Find particular half of the globe (down) Spin antinu-RH Pnu pe Spin e - LH Co P461 - rots II

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180 o - q reflect Discovery of Parity Violation in Beta Decay by C.S. Wu et al . Test equality preservation by watching a reliance of a rot rate (or cross segment) on a term that progressions sign under the equality operation. In the event that rot rate or cross area changes under equality operation, then the equality is not preserved. Equality switches momenta and positions yet not rakish momenta (or twists). Turn is a pivotal vector and does not change sign under equality operation. Beta rot of a neutron in a genuine and reflect universes: If equality is preserved, then the likelihood of electron discharge at q is equivalent to that at 180 o - q . Chosen introduction of neutron twists - polarization. P e neutron P e P461 - rots II

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Wu's investigation Beta-rot of 60 Co to 60 Ni * . The energized 60 Ni * rots to the ground state through two progressive g discharges. Cores energized through turn arrangement in an expansive attractive field at 0.01 o K. At low temperature warm movement does not decimate the arrangement. Polarization was exchanged from 60 Co to 60 Ni cores. Level of polarization was measured through the anisotropy of gamma-beams. Beta particles from 60 Co rot were recognized by a thin anthracene precious stone (scintillator) put over the 60 Co source. Glimmers were transmitted to the photomultiplier tube (PMT) on top of the cryostat. P461 - rots II

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Wu's outcomes Graphs: top and center - gamma anisotropy (contrast in numbering rate between two NaI precious stones) - control of polarization; base - b asymmetry - including rate the anthracene gem in respect to the rate without polarization (after the set up was warmed up) for two introductions of attractive field. Comparative conduct of gamma anisotropy and beta asymmetry. Rate was diverse for the two attractive field introductions. Asymmetry vanished when the precious stone was warmed up (the attractive field was still present): association of beta asymmetry with turn introduction (not with attractive field). Beta asymmetry - Parity not rationed P461 - rots II

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Gamma Decays If something (beta/alpha rot or a response) places a core in an energized state, it drops to the most reduced vitality through gamma outflow energized states and rots like molecules ration precise energy and equality photon has turn =1 and equality = - 1 for orbital P= (- 1) L first request is electric dipole minute (edm). Less demanding to have higher request terms in cores than molecules P461 - rots II

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Gamma Decays 5 26% E MeV 11% gamma 53% gamma 0 moderate rakish energy and equality. most reduced request is electric dipole minute. at that point quadrapole and attractive dipole P461 - rots II

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Mossbauer Effect Gamma rots ordinarily have lifetimes of around 10 - 10 sec (expansive range). Gives width: extremely exact if free cores rots, need to monitor energy. Shifts gamma vitality to marginally bring down esteem case. Small move yet more noteworthy than common width P461 - rots II

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Mossbauer Effect II Energy move implies a transmitted gamma won't be reabsorbed yet in the event that core is in a precious stone lattic, then whole cross section draws back against photon. Mas(lattice) ��  endlessness and Egamma=deltaM. Recoiless discharge (or Mossbauer) will have "wings" on photon vitality because of cross section vibrations Mossbauer impact can be utilized to study grid enregies. Extremely exact. Use as emitter or safeguard. Change vitality by moving source/target (Doppler move) (utilize Iron. created by R. Preston, NIU) P461 - rots II

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Nuclear Reactions, Fission and Fusion 2 Body response A+B ��  C+D flexible if C/D=A/B inelastic if mass(C+D)>mass(A+B) limit vitality for inelastic (B very still) for cores nonrelativistic as a rule OK P461 - rots II

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Nuclear Reactions (SKIP) A+B ��  C+D estimation of kinematic amounts permits masses of conclusive states to be resolved (p,E) beginning A,B known 8 questions in definite state (E,px,py,pz for C+D) yet E,p monitored. 4 requirements ��  4 questions measure E,p (or mass) of D OR C gives rest or measure pc and pd gives masses of both frequently simplest to take a gander at precise appropriation in C.M. be that as it may, can simply change over P461 - rots II

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Fission A ��  B+C An overwhelming, B/C medium cores discharges vitality as restricting vitality/nucleon = 8.5 MeV for Fe and 7.3 MeV for Uranium unconstrained splitting resemble alpha rot however with various mass, radii and Coulomb (Z/2) 2 versus 2(Z-2). Low rate for U, higher for bigger An initiated parting n+A ��  B+C. The neutron includes its coupling vitality (~7 MeV) a

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