All Questions
Tagged with scattering-cross-section standard-model
21
questions
2
votes
0
answers
43
views
$hh \to hh$ scattering
I'm trying to compute the double Higgs scatter in QFT framework. Is it correct if I use the scalar propagator for this process?
Also I've found that I've four possible diagrams: the three $s,t,u$ ...
- 41
1
vote
1
answer
100
views
Inverse muon decay on Mandl shaw- Help on $W$ boson propagator
Hello, I cannot understand why here the other term of the propagator of $W$ boson $k^{\alpha} k^{\beta}/m_{W}^{2}$ is not present, and how/if this absence is linked to the fact that we neglect terms ...
- 11
5
votes
0
answers
230
views
Another "real vs virtual particle" one: calculate the full diagram or $\sigma \times \mathrm{BR}$?
I have recently been forced to think about something I always thought that I understood but that, in reality, I could not be more confused about.
Suppose I want to study the LHC prospects for ...
- 1,742
0
votes
0
answers
50
views
Amplitude of the process $q \bar q \rightarrow \tau^+ \tau^-H$
I want calculate the cross section of the process $q \bar q \rightarrow \tau^+ \tau^-H$, where the Higgs takes the $vev$. My question is: if the Higgs takes the $vev$ the amplitude of the process is ...
- 11
-1
votes
1
answer
123
views
Integral on phase space
I'd like to integrate the square amplitude in the phase space( in $d^3k/(2\pi)^3 2E_k$ and $d^3k'/(2\pi)^3 2E_k$) where $p$ and $p'$ are the 4-momentum of the input particles, $k$ and $k'$ 4-momentum ...
- 11
0
votes
1
answer
102
views
Testing the Standard Model Lagrangian
When we measure cross-sections of Standard Model predicted processes, are we actually only testing the interaction terms of the corresponding Lagrangian?
- 363
1
vote
1
answer
80
views
The Standard Model Lagrangian vs experimental results
In the Standard Model of particle physics, one always shows the general SM Lagrangian and claims that the SM can be summarised in the expression. But it's not clear to me how this is actually verified ...
- 363
2
votes
1
answer
112
views
Why do strangeness producing reactions have a small cross section?
My professor told me that kaon producing reactions have a small cross section compared to other nucleon collision reactions. The reason for that is the production of a strange quark but he didn't ...
2
votes
0
answers
68
views
Why is the $Z$ resonance cross section so much larger for hadrons? [duplicate]
The image shows experimental data for the ratio of cross sections $$R=\frac{\sigma(e^+e^-\rightarrow\text{hadrons})}{\sigma(e^+e^-\rightarrow\mu^+\mu^-)}.$$
I am wondering why $R$ is so large for the $...
- 2,122
0
votes
2
answers
401
views
How is strong coupling constant related to cross section?
I've been looking through different Pdfs /articles on strong coupling constant and nearly all of them involve cross section, I've understood what cross section is but not how is it connected to ...
- 141
2
votes
2
answers
396
views
Suppression of $W$ boson propagator by its mass
In my experimental particle physics introductory class it was often said that quantum electrodynamics (QED) is very predictive for sufficiently small center of mass energys since the $W^\pm$-...
- 2,196
2
votes
1
answer
257
views
Crossing Symmetry between tree-level diagrams of $e^+ e^- \rightarrow \mu^+ \mu^-$ and $e^- \mu^- \rightarrow e^- \mu^-$
According to Peskin and Schroeder (P&S)'s book, on pp. 156-157, the two processes $e^+ e^- \rightarrow \mu^+ \mu^-$ and $e^- \mu^- \rightarrow e^- \mu^-$ are connected via $s \leftrightarrow t$ ...
- 353
-1
votes
1
answer
56
views
Where can I find inclusive $p^+p^+ \to W^+W^-+X^{++}$ cross-section prediction at $14 TeV$ (NNLO)?
The title self explains.. I desperately need the theoretical NNLO (also NLO can work) prediction for inclusive diboson production (WW), a link to a paper would make my week!
1
vote
0
answers
667
views
Computing the decay width for Top quark decaying to bottom quark and W boson
I have been trying to calculate the decay width for the $t \rightarrow bW^+$ decay. After having done this numerous times, I can not figure out how the result
$$\Gamma = \frac{g^2m_t^3}{64\pi m_W^2}\...
- 127
0
votes
1
answer
196
views
Cross-section for $t\bar{t}H$
I often see precision measurements of the $t\bar{t}H$ process at the (HL-)LHC justified by the statement that "it's the only cross-section that's directly proportional to the Higgs-top Yukawa coupling"...
- 1,379