<div dir="ltr">As requested the beam energy used for these corrections was 10.6041 GeV.<div><br></div><div>Thanks,</div><div>Geraint Clash.</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, 15 Apr 2020 at 17:56, Geraint Clash <<a href="mailto:geraintclash@gmail.com">geraintclash@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Hello all,<br><br>I have re-done the energy correction I shared with you previously but using pass 1 data from this path: /volatile/clas12/users/devita/2pi/rga-pass1v0/skim3/. I have used the following function to produce the attached plots: <br><br>TLorentzVector Correct_Electron(TLorentzVector x){<br><br> Double_t E_new, Px_el, Py_el, Pz_el;<br> TLorentzVector el_new;<br><br> E_new = x.E()-0.03689+0.1412*x.E()-0.04316*pow(x.E(),2)+0.007046*pow(x.E(),3)-0.0004055*pow(x.E(),4);<br><br> Px_el = E_new*(x.Px()/x.Rho());<br> Py_el = E_new*(x.Py()/x.Rho());<br> Pz_el = E_new*(x.Pz()/x.Rho());<br><br> el_new.SetXYZM(Px_el, Py_el, Pz_el, 0.000511);<br><br> return el_new;<br>} <br><br>then calling the function like this Correct_Electron(measured electron TLorentzVector) and that goes in place of the measured electron TLorentzVector.<br><br>The attached file is a short presentation containing the following: The separate missing mass of everything and the proton plots fitted to show the mean and sigma, for both the original and corrected cases. Then the missing mass plots unfitted on the same axis where red is the original. Finally, the delta energy plots where the corrected is on the left.<br><br>Thanks,<br>Geraint Clash.</div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, 15 Apr 2020 at 15:10, nicholas <<a href="mailto:nicholas@jlab.org" target="_blank">nicholas@jlab.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div>Hi Will, <div><br></div><div>We have no indication that the angles are wrong as these are established from the clusters. We understand how the energy is off in the FT and I think at this stage an initial correction that Geraint is working on is sufficient to start looking at things in much more detail. Raffaella came up with a different energy reconstruction, which accounts for some of this difference, but it is not sufficient to correct for it in its entirety. By no means the correction that Geraint will send soon is the final one and he will work on more studies using higher stats. I think the way the correction is determined/applied is not very crucial especially since in your plot there is still a significant slope and it doesnt seem to be a scale factor independent of E.</div><div><br></div><div>Cheers,</div><div>-N</div><div><br><div><br><blockquote type="cite"><div>On 15 Apr 2020, at 15:00, William Phelps <<a href="mailto:wphelps@jlab.org" target="_blank">wphelps@jlab.org</a>> wrote:</div><br><div>
<div>
Hello Geraint,
<div><br>
</div>
<div>I have been thinking about this electron correction (briefly). It seems to me that it would make sense to have the correction as a ratio P_missing/P_reconstructed as a function of P_reconstructed. So all we would need to do is scale the electron
momentum (and recalculate energy). You mentioned that you are going to take another look at your correction during the meeting, is this what you are thinking about doing? </div>
<div><br>
</div>
<div>I attached a 2d histogram that might make more sense than what I said in the paragraph above.</div>
<div><br>
</div>
<div>A secondary question to the group: If the reconstructed momentum is incorrect does this mean that the angle is also incorrect?</div>
<div><br>
</div>
<div>Thanks,</div>
<div>-Will</div>
<div><br>
</div>
<div><span id="gmail-m_-906068193264393714gmail-m_8379600386510614204cid:F253E635-7957-40F7-B576-8A35BD3956D6"><Plot_04-15-2020_09.53.13_AM.png></span><br>
<div><br>
<blockquote type="cite">
<div>On Apr 3, 2020, at 9:58 AM, Geraint Clash <<a href="mailto:geraintclash@gmail.com" target="_blank">geraintclash@gmail.com</a>> wrote:</div>
<br>
<div>
<div dir="ltr">
<div>Hello all,<br>
</div>
<div><br>
</div>
I carried out a study on the difference between the energy of the electron when you treat it as missing and the measured electron using skim3 data from this path: /volatile/clas12/users/clas12/rich/dst/recon/005038/. For this, the exclusive reaction ep->e’p
pi+pi- was selected, with three-sigma cuts around missing mass squared of all products and the missing mass of the proton.<br>
The plot of the difference in energy ("missing" electron - detected electron) against the electron measured energy is the attached file Del_E. Y-projections were fitted with Gaussians and the means were fitted with a fourth-order polynomial establishing the
correction function (see attached).<br>
<br>
The energy correction which should be added to the measured electron energy, E, is: -0.0004x^4+0.0071x^3-0.0432x^2+0.1356x-0.0257. <br>
<div><br>
</div>
<div>Thanks,</div>
<div>Geraint Clash.</div>
</div>
<span id="gmail-m_-906068193264393714gmail-m_8379600386510614204cid:f_k8k8c6dz1"><Del_E_mean_fit.png></span><span id="gmail-m_-906068193264393714gmail-m_8379600386510614204cid:f_k8k8c6df0"><Del_E.png></span>_______________________________________________<br>
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