Recent content by bomanfishwow

You also have the case where you have a quark-gluon initial state, where the gluon splits into a quark anti-quark pair. The anti-quark then interacts with a quark from the other proton to give the Drell-Yan part, along with an associated jet in the final state from the 'left-over' quark. Note...

Ah yes, very elegant. Thanks!

Sure, but I'm interested in showing why this is the case mathematically...

So, a mixed term is something like \bar{\psi}\gamma^\mu\left(1-\gamma^5\right)\psi? How can it be shown that this term violates parity? Cheers.

Hi, I'm trying to remind myself of exactly what, physically, is the difference between V and A couplings. Now, a vector coupling is of the form \bar{\psi}\gamma^\mu\psi, and axial coupling of the form \bar{\psi}\gamma^\mu\gamma^5\psi. Thinking in terms of a chiral fermion expanded as: f...

It's strongly peaked in the pi0 rest frame, but they are 'never' at rest in a pp collision. I think you'll find it's the intrinsic pi0 boost which produces the spectrum.

Ah yes of course, thank you.

I'm taking 5 mins (hours) during some down-time to remind myself of some theory. Taking a simple Abelian Higgs model, where the Lagrangian is given by: \mathcal{L} = |D_\mu\Phi|^2 - \frac{1}{4}F_{\mu\nu}F^{\mu\nu} - V(\Phi) With the covariant derivative, field strength tensor and potential...

CalcHEP (http://theory.sinp.msu.ru/~pukhov/calchep.html) will take you from the Feynman rules to calculations of cross sections, distributions, event generation etc. However, I suggest a tame theorist / phenomenologist to prepare models for you!

But the problem here is that there is NO phenomenology that points to lepton compositness, therefore it is fundamental. These results are always interpreted in the limits of the available energy to probe the object; that is understood by all in the field. People are going to be looking at the...

Depends on just how much you want to disentangle. It's fairly easy (given enough integrated luminosity) to measure the spin and couplings of any new resonance from the decay kinematics, and this constrains things hugely. I.e. Spin 1 implies a new U(1) like thing, Spin 2 implies (amongst other...

I respectfully disagree with the post above. Many GUTs include decompositions such as (and as a very simple example): SO(10) \to SU(5) \otimes U(1)_{GUT} \to SU(3) \otimes SU(2) \otimes U(1)_{Y} \otimes U(1)_{GUT} The new U(1) would exhibit itself as a new neutral current process (so...

Oooo, a tame lump of neutron star?

Yes indeed, I was talking explicitly about Z/W interaction terms - I didn't want to get into the fact the U(1)s are different in each case!

I presume you are meaning something related to this measurement? http://www.fnal.gov/pub/today/archive_2008/today08-08-21.html Nobody has claimed that di-boson production implies a bound state. What is happening is illustrated by the feynman diagram here...