Timeline for What do we mean by fit of data in particle physics?
Current License: CC BY-SA 3.0
9 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Nov 9, 2017 at 15:46 | comment | added | anna v | Have a look at this cds.cern.ch/record/2217139/files/9789814733519_0008.pdf , elaborate fits use all channels, it is just that the hadronic channels are dominant and that the number of neutrinos affect the peak crossection. | |
| Nov 9, 2017 at 15:10 | comment | added | kbg | Thank you for the reply!!Also, was there any deep meaning as of why only they took Z decay to hadrons? We could have taken Z decay to leptons and then taken the decay width of Z to hadrons from standard model and all other parameters as we did earlier.(I am referring to the ALEPH plot, or even the plot you attached, both of which measures the cross section for only hadronic channel.) | |
| Nov 9, 2017 at 14:36 | comment | added | anna v | I have included that plot in my answer in an edit after my last comment. Yes, they use the standard model to predict the differences if the theory had two, three, or four neutrinos, with free parameters only the numberof neutrinos and the total crossection of the Z; and the best fit is the three. | |
| Nov 9, 2017 at 8:09 | comment | added | kbg | Sir, I have added a plot in the question. Does, it mean that except $m_z,N_\nu$ and peak cross section, all other factors (including decay width of z to leptons and decay width of z to $\nu\bar{\nu}$ was taken from the standard model? | |
| Nov 7, 2017 at 19:37 | vote | accept | kbg | ||
| Nov 7, 2017 at 4:44 | history | edited | anna v | CC BY-SA 3.0 |
edit after comment
|
| Nov 7, 2017 at 4:38 | comment | added | anna v | When one is doing a fit in a complex problem some parameters are left free to be determined by the fit. Normally for fitting the Z or the H or ... one leaves as free the first (called little model dependence, i.e. it is mostly kinematics). To determine whether there are two or three or four neutrinos, the values of all parameters were fixed by the standard model except for the crossection and then three different models were applied, with two neutronos three or four . | |
| Nov 6, 2017 at 20:32 | comment | added | kbg | Sir, could you explain the last paragraph again... that is about two parameter and three parameter fit..(like which are those two or three parameters here...I guess two of them are $m_Z$ and $N_\nu$ as you mentioned. So what is the third parameter?) | |
| Nov 6, 2017 at 19:54 | history | answered | anna v | CC BY-SA 3.0 |