What is Z boson: Definition and 26 Discussions

In particle physics, the W and Z bosons are vector bosons that are together known as the weak bosons or more generally as the intermediate vector bosons. These elementary particles mediate the weak interaction; the respective symbols are W+, W−, and Z0. The W± bosons have either a positive or negative electric charge of 1 elementary charge and are each other's antiparticles. The Z0 boson is electrically neutral and is its own antiparticle. The three particles have a spin of 1. The W± bosons have a magnetic moment, but the Z0 has none. All three of these particles are very short-lived, with a half-life of about 3×10−25 s. Their experimental discovery was pivotal in establishing what is now called the Standard Model of particle physics.
The W bosons are named after the weak force. The physicist Steven Weinberg named the additional particle the "Z particle", and later gave the explanation that it was the last additional particle needed by the model. The W bosons had already been named, and the Z bosons were named for having zero electric charge.The two W bosons are verified mediators of neutrino absorption and emission. During these processes, the W± boson charge induces electron or positron emission or absorption, thus causing nuclear transmutation.
The Z boson mediates the transfer of momentum, spin and energy when neutrinos scatter elastically from matter (a process which conserves charge). Such behavior is almost as common as inelastic neutrino interactions and may be observed in bubble chambers upon irradiation with neutrino beams. The Z boson is not involved in the absorption or emission of electrons or positrons. Whenever an electron is observed as a new free particle, suddenly moving with kinetic energy, it is inferred to be a result of a neutrino interacting directly with the electron, since this behavior happens more often when the neutrino beam is present. In this process, the neutrino simply strikes the electron and then scatters away from it, transferring some of the neutrino's momentum to the electron.

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  1. S

    A Does the Z boson pole show up in the photon propagator?

    If I look at the photon propagator <A_mu (x) A^nu(0) > in momentum space, as I understand it I am to compute this by summing up all the self-energy diagrams of the photon, which look like: photon -> stuff -> photon In particular, since the photon shares the same quantum numbers as the Z, you...
  2. W

    I How to derive the currents of Z boson and the EM current?

    I am a student minor in physics and I am taking this course of particle physics. And I have been lost since the Non-Abelian Gauge Theory which a few lectures before Electroweak unified Theory lecture. i am completely confused and overwhelmed by the math since the mid-term exam, since I was not...
  3. C

    I Why is the Z Boson represented triangular in this diagram?

    Hi The diagram I am referring is shown at 1:45 of this classic Symphony of Science tune Thanks, Cal
  4. I

    I Can a Z Boson Decay to a Photon Affect Its Weak Charge?

    If a Z can decay to a photon, what happens to the Z's weak charge?
  5. andrex904

    Exploring Parity & Charge Conjugation in Z Boson Decay

    Considering a Z boson decay into a fermion-antifermion pair. How can i say if the process respect parity and charge conjugation?Thanks
  6. M

    SM neutrinos coupling to Z boson

    Hi All 1. Homework Statement with the known coupling strenght between SM neutrinos and Z boson Z_{\mu} \bar{\nu}_{L} { \gamma}^{ \mu} \nu_{L} how can I get the coupling strength for Dirac neutrinos Z_{\mu} \bar{\nu}_{Dirac} { \gamma}^{ \mu} (1- { \gamma}_{ 5} ) \nu_{Dirac} ? thanks
  7. U

    Production of Z boson - Cross Section

    Homework Statement Calculate the ratio ##R = \frac{\sigma_{had}}{\sigma_{\mu+\mu-}}## for energy around ##10~GeV##. At sufficiently high energies, the ##e^+e^- \rightarrow \mu^+ \mu^-## reaction can proceed via the ##Z^0## boson. Assuming vertex factors for EM and weak interaction are the same...
  8. AlanKirby

    How can e-e+ possibly go to ZZ?

    Hi there, my question is the following. If an electron and positron annihilate, how can they result in ZZ? The issue I'm having is that due to charge conservation, the exchange particle can't be W- or W+. It also can't be a photon since the Z's don't have electrical charge to couple to. It...
  9. sk1105

    Why is the electroweak cross-section zero at Z boson mass?

    The Standard Model formula for the cross-section of ##e^+e^-\rightarrow\mu^+\mu^-## is made up of 3 components: QED interactions, weak interactions, and electroweak interference. I understand the behaviour of the QED part, and the resonance that occurs in the weak part at ##\sqrt{s}=M_Z##, but...
  10. R

    How do the W and Z Gauge Bosons work in the weak nuclear force?

    I've seen explanations that when a neutrino with a W+ Boson comes near a neutron, it affects one of the bottom quarks and changes it to a up quark which effectively turns the neutron into a proton. The neutrino then turns into an electron. Source: (2:20 onwards) I've seen other explanations...
  11. N

    Can the Z Boson Change Particle Flavors?

    I have read that the Z boson cannot change the flavour of a particle. So my assumption is that an interaction such as: usanti -> udanti + Z Is not possible, is this correct?
  12. J

    Simulation of pp-collision and Z boson production

    Hi all, I have a question about simulating (Monte Carlo) proton-proton collisions resulting in, for example, a Z boson. Assume two quarks (quark and antiquark) from each proton collide head-on along the z-axis. The quark momenta are distributed according to the Parton Density Functions...
  13. C

    How Does the Mass of the Bottom Quark Affect Z Boson Decay Calculations?

    Hello everyone, I have read about the theoretical values of the Z boson decay partial width and how well they agreed with experiment. However there is something I do not quite understand: since these theoretical calculations were performed with the hypothesis that the masses of the decay...
  14. T

    Zee.csv Meaning on CERN Webpage - Stats Project Help

    Could someone please tell me what the symbols in the Zee.csv file mean on the CERN webpage (https://cms-docdb.cern.ch/cgi-bin/PublicDocDB/ShowDocument?docid=11581)? I am doing a project for my statistics class and that information would be useful. I'll appreciate any and all help.
  15. Y

    Decay rate and lifetime of Z Boson

    What are the accepted numbers for the decay rate and lifetime of Z-> mu+mu- and Z-> e+e- decays? also what is the unit for the decay rate? thank you!
  16. C

    Why Does Z Boson Only Decay to Fermion-Antifermion Pairs?

    Why does the Z boson only decay to fermion-antifermion pairs? I'd just like to understand the basic reason why something like Z --> anti-down, strange wouldn't work. This would conserve charge. It obviously wouldn't conserve strangeness, but the weak interaction doesn't, so I'm just wondering...
  17. D

    Finding Range of Weak Interaction from Mass of Z Boson

    Homework Statement One of the mediators of the weak interactions is the Z boson, which has a mass of 91 GeV/c 2. Use this information to find an approximate value for the range of the weak interaction. Homework Equations This is the part that I am having trouble with. I don't know where to...
  18. D

    Net Effect of Z Boson on Charged Particles

    I was always wondering, on very short distances/high energies, what is a net effect of having not one (gamma) but two (gamma and Z) 'carriers' for the 'force' between 2 charged particles. Does it make an interaction sronger or not?
  19. J

    What particles can the Z boson couple to in the standard model?

    Hi just wondering if anyone could tell me why the Z boson can couple to any standard model particle except forgluons and photons?
  20. E

    Why More W^+/- than Z^0 in Proton-Antiproton Collisions?

    Can someone give me a qualitative/handwaving argument of why much more W^+/- boson are produced in proton-antiproton collisions compared to Z^0 bosons? PDFs are not enough to explain this I believe, since we will have more u ubar pairs in the collision than u dbar... Also if I...
  21. M

    Does the Z boson couple to photons?

    Hi I can't find a Feynman rule for the coupling of two Z bosons to a photon. Does the Z boson couple to a photon at all?
  22. M

    Z Boson, Posiron-Electron Annihilation.

    Suppose I want to find the minimum velocity of the electron and positron required to make a Z boson during annihilation. How would I go about this? I had an attempt which came out at 422ms^-1. This doesn't really seem right... so I'm guessing i made a big mistake...
  23. P

    Angle pd decay between two muons between Z boson?

    Question leads on from others where s^1/2 = 200GeV mH = 70GeV EH = 91.5GeV and p = 59GeV, (three momentum). The reaction was e+e- -> HZ0 where H is higgs boson and Z0 is the Z0 boson with mass 91GeV It says the Z0 decays to two muon and antimuon. They are observed to be equal energy in...
  24. K

    Understanding the Higgs Mechanism: W & Z Boson Mass & Particle Mass

    I need help understanding the Higgs mechanism: what is the Higgs condensate, what is the Higgs boson, why do only the W and Z bosons have mass, and how exactly do particles receive mass? thanks guys!
  25. malawi_glenn

    W and Z boson production and decay at e-e+ collider

    Hi! I was wondering how W+/- pairs can be created in an electron/positron collider. Does the e+e- form a Z^0 which decays to W^- W^+ ? http://www.particle.kth.se/zlab/project/Elep.gif I have found this picture, but there is no info about the mediating particle (in the small...
  26. H

    Why was is it needed to include the Z boson along with the W's?

    Why was is it needed to include the Z boson along with the W's... is the theory nonrenoramalizable without it?