Jet calibration and dijet mass invariant mass

[caredg]

There is an issue with the reconstruction of the invariant mass of the Z boson from the signal samples.
As it can be seen here, the peak is off-scale. This plot was obtained using the gen-matched reco jets in our signal sample of 200GeV LW. This is puzzling because the calibration correction for jets was used.

[caredg]

I will make a new ntuple, just for this 200GeV LW sample but using the PAT routine to check if that is the problem.

[caredg]

@JonaJJSJ-crypto we need to compare the pT of the gen jets and the reco jets. Please also add here any other piece of information that you may have

[JonaJJSJ-crypto]

The matching is not perfect there is some wrong matche jetsBut i think this is minimun

[caredg]

I produced a new WZJetsTo2L2Q.root ntuple, which was run using the PAT routines. @JonaJJSJ-crypto please check what this new ntuple gives for the di-jet mass of the Z. It is in the same cernbox place under signalStudy_round7. Also find it at the cajuela location in about 30 minutes.

[JonaJJSJ-crypto]

For Completeness I can include the Correct Dijet invariant mass for this Dataset before the pat processing. Notice that signal dijet selects the jets that better fit Z Daugthers

[caredg]

For Completeness I can include the Correct Dijet invariant mass for this Dataset before the pat processing. Notice that signal dijet selects the jets that better fit Z Daugthers

What is the difference between the 3 plots? What changes in each?

[caredg]

Ok, at least it seems consistent with the LW signal sample, which is good (on one side) because this indicates that is not only our signal that suffers the problem.

[JonaJJSJ-crypto]

I produced a new WZJetsTo2L2Q.root ntuple, which was run using the PAT routines. @JonaJJSJ-crypto please check what this new ntuple gives for the di-jet mass of the Z. It is in the same cernbox place under signalStudy_round7. Also find it at the cajuela location in about 30 minutes.

@caredg I had already check the invariant mass with PAT routine for WZ, but the invariant mass is still displace, yet here the corrections seems to be more relevant correcting the scale from uncorrected jets. Since the invariant mass reconstructed with electrons seems to be ok, I'm assuming there is no problem with the method used to calculate the invariant mass. Here the results

[caredg]

@JonaJJSJ-crypto, this line, in the poet config file, advices to run the jec_cfg.py file first, in order to get the txt files with the corrections. Although this was allegedly done already, can you check that, if you run it again, you get the same results as thoxe stored in the JEC folder?

[JonaJJSJ-crypto]

@JonaJJSJ-crypto, this line, in the poet config file, advices to run the jec_cfg.py file first, in order to get the txt files with the corrections. Although this was allegedly done already, can you check that, if you run it again, you get the same results as thoxe stored in the JEC folder?

I had Check all the produced files with MC they are all the same.

[JonaJJSJ-crypto]

I have been checking the invariant mass of W boson decaying into 2 quarks. I will present the distributions fore Reco and Generated invariant mass. As you may see in the Reco Distribution the peak is not as sharp as that seem in Z Boson, yet this is most center in the correct invariant mass. I manage to clean the Signal by strictly picking the two most jets comming the W boson. la Joroba a la izquierda se debe a los casos en los que solo se encuentra un jet. Se puede ver que la Masa invariante elrededor de los 85GeV

[JonaJJSJ-crypto]

@caredg Aqui voy a presentar las distribuciones en pt para los jets reconstruidos, tanto con momento corregido como sin corregir. Y ademas su correspondiente quark generado hijo de Z. Se puede ver que la correccion de momento en jets acerca las distribuciones hacia la distribucion de la generacion. Pero esta a medio camino

[JonaJJSJ-crypto]

@caredg Ademas hice el analisis inverso, Tomando las hijas del boson Z tome la distribucion de momentos y de su correspondiente mejor match en jet reconstruido. El aspecto es el mismo para este caso tambien. Es decir, que el momento de las particulas reconstruidas esta desplazado a la derecha y que la correccion soluciona parcialmente esto.

[JonaJJSJ-crypto]

@caredg Aqui presento los histogramas bidimencionales de pt del jet mas energetico vs pt de hijas de z que mejor matchean a este jet. Y lo mismo que antes pero con el pt corregido.

[JonaJJSJ-crypto]

@caredg Estudi la diferencia entre el ramal principal de jets bien matchaedos con el ramal secundario que aparece en la entrada previa. Como se puede observar el algoritmo de match indica que geometricamente tanto el jet reconstruido como los quarks hijos de Z coinciden en trayectoria pero no en momento. Para averiguar la causa de esto y determinar si esto esta afectando la calibracion del momento de los jets, se hizo el siguiente estudio. Basado en la hipotesis que los jets reconstruidos tienen un momento superior al esperado debido a que hay otro objeto que ocupa el mismo espacio fisico. Para ello en el caso de un jet mal matcheado se grafico la distancia al electron mas cercano, energia fraccionaria electromagnetica. Y efectivamente parece ser que una causa para este fenomeno el jet mal matcheado podria ser la superposicion de jet con electron. A continuacion presentare estas cantidades donde la terminologia AR se refiere a jets mal matcheados por anomalous region. Como se puede ver en el caso de los Jets mal matcheados mayoritariamente una distacia geometrica a los elctrones casi 0 y se ve que tienen un porcion anormal en cuando a energia fracionaria electromagnetica. Esto apoya a la hipotesis antes planteada, y con ello se busco hacer un corte en Energia Electromagnetica fraccionaria(EMF<0.6) para ver si afecta en la distribucion de momento de los jets Sin mebargo, parecio no haber ningun efecto. Ademas, tambien se corrobora si esto afecta el match de los jets. Se puede ver que el corte en EMF<0.6 contribuye para filtrar los jets mal matcheados pero esto no contribuye en la calibracion de los jets