The performance of missing transverse momentum reconstruction and its significance with the ATLAS detector using 140 $$\hbox {fb}^{-1}$$ of $$\sqrt{s}=13$$ TeV pp collisions
G. Aad, Erlend Aakvaag, B. Abbott, K. Abeling, Nils Julius Abicht, S. H. Abidi, A. Aboulhorma, H. Abramowicz, H. Abreu, Y. Abulaiti, B. S. Acharya, C. Adam Bourdarios, L. Adamczyk, S. V. Addepalli, M. J. Addison, J. Adelman, A. Adıgüzel, T. Adye, A. A. Affolder, Y. Afik, M. N. Agaras, J. Agarwala, A. Aggarwal, C. Agheorghiesei, A. Ahmad, F. Ahmadov, W. S. Ahmed, S. Ahuja, X. Ai, G. Aielli, A. Aikot, M. Ait Tamlihat, B. Aitbenchikh, I. Aizenberg, M. Akbiyik, T. P. A. Åkesson, A. V. Akimov, D. Akiyama, Nilima Nilesh Akolkar, S. Aktas, K. Al Khoury, G. L. Alberghi, J. Albert, P. Albicocco, Guillaume Lucas Albouy, S. Alderweireldt, Z. L. Alegria, M. Aleksa, I. N. Aleksandrov, C. Alexa, T. Alexopoulos, F. Alfonsi, M. Algren, M. Alhroob, B. Ali, H. M. J. Ali, S. Ali, Samuel William Alibocus, M. Aliev, G. Alimonti, W. Alkakhi, C. Allaire, B. M. M. Allbrooke, Julia Frances Allen, C. Flores, P. P. Allport, A. Aloisio, F. Alonso, C. Alpigiani, M. Alvarez Estevez, A. Álvarez Fernández, Mario Alves Cardoso, M. G. Alviggi, M. Aly, Y. Amaral Coutinho, A. Ambler, C. Amelung, M. Amerl, C. G. Ames, D. Amidei, S. P. Amor Dos Santos, K. R. Amos, V. Ananiev, C. Anastopoulos, T. Andeen, J. K. Anders, S. Y. Andrean, A. Andreazza, S. Angelidakis, A. Angerami, A. V. Anisenkov, A. Annovi, C. Antel, M. T. Anthony, E. Antipov, M. Antonelli, F. Anulli, M. Aoki, T. Aoki, J. A. Aparisi Pozo
Abstract
Abstract This paper presents the reconstruction of missing transverse momentum ( $$p_{\text {T}}^{\text {miss}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>p</mml:mi> <mml:mrow> <mml:mtext>T</mml:mtext> </mml:mrow> <mml:mtext>miss</mml:mtext> </mml:msubsup> </mml:math> ) in proton–proton collisions, at a center-of-mass energy of 13 TeV. This is a challenging task involving many detector inputs, combining fully calibrated electrons, muons, photons, hadronically decaying $$\tau $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>τ</mml:mi> </mml:math> -leptons, hadronic jets, and soft activity from remaining tracks. Possible double counting of momentum is avoided by applying a signal ambiguity resolution procedure which rejects detector inputs that have already been used. Several $$p_{\text {T}}^{\text {miss}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>p</mml:mi> <mml:mrow> <mml:mtext>T</mml:mtext> </mml:mrow> <mml:mtext>miss</mml:mtext> </mml:msubsup> </mml:math> ‘working points’ are defined with varying stringency of selections, the tightest improving the resolution at high pile-up by up to 39% compared to the loosest. The $$p_{\text {T}}^{\text {miss}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>p</mml:mi> <mml:mrow> <mml:mtext>T</mml:mtext> </mml:mrow> <mml:mtext>miss</mml:mtext> </mml:msubsup> </mml:math> performance is evaluated using data and Monte Carlo simulation, with an emphasis on understanding the impact of pile-up, primarily using events consistent with leptonic Z decays. The studies use $$140~\text {fb}^{-1}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>140</mml:mn> <mml:mspace/> <mml:msup> <mml:mtext>fb</mml:mtext> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> of data, collected by the ATLAS experiment at the Large Hadron Collider between 2015 and 2018. The results demonstrate that $$p_{\text {T}}^{\text {miss}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>p</mml:mi> <mml:mrow> <mml:mtext>T</mml:mtext> </mml:mrow> <mml:mtext>miss</mml:mtext> </mml:msubsup> </mml:math> reconstruction, and its associated significance, are well understood and reliably modelled by simulation. Finally, the systematic uncertainties on the soft $$p_{\text {T}}^{\text {miss}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>p</mml:mi> <mml:mrow> <mml:mtext>T</mml:mtext> </mml:mrow> <mml:mtext>miss</mml:mtext> </mml:msubsup> </mml:math> component are calculated. After various improvements the scale and resolution uncertainties are reduced by up to $$76\%$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>76</mml:mn> <mml:mo>%</mml:mo> </mml:mrow> </mml:math> and $$51\%$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>51</mml:mn> <mml:mo>%</mml:mo> </mml:mrow> </mml:math> , respectively, compared to the previous calculation at a lower luminosity.