Search for heavy Majorana or Dirac neutrinos and right-handed W gauge bosons in final states with charged leptons and jets in pp collisions at $$\sqrt{s}=13$$ TeV with the ATLAS detector
G. Aad, B. Abbott, K. Abeling, Nils Julius Abicht, S. H. Abidi, A. Aboulhorma, H. Abramowicz, H. Abreu, Y. Abulaiti, A. C. Abusleme Hoffman, B. S. Acharya, C. Adam Bourdarios, L. Adamczyk, L. Adámek, Sagar Addepalli, Matt Addison, J. Adelman, Aytul Adiguzel, T. Adye, A. A. Affolder, Yoav Afik, M. N. Agaras, J. Agarwala, A. Aggarwal, C. Agheorghiesei, A. Ahmad, F. Ahmadov, W. S. Ahmed, S. Ahuja, X. Ai, G. Aielli, M. Ait Tamlihat, B. Aitbenchikh, I. Aizenberg, M. Akbiyik, T. P. A. Åkesson, A. V. Akimov, Daiya Akiyama, Nilima Nilesh Akolkar, K. Al Khoury, G. L. Alberghi, J. Albert, P. Albicocco, Guillaume Lucas Albouy, S. Alderweireldt, M. Aleksa, I. N. Aleksandrov, C. Alexa, Theodoros Alexopoulos, A. Alfonsi, F. Alfonsi, M. Algren, M. Alhroob, B. Ali, Hanadi Ali, S. Ali, Samuel William Alibocus, M. Aliev, G. Alimonti, W. Alkakhi, C. Allaire, Benedict Allbrooke, Julia Frances Allen, C. Flores, P. P. Allport, A. Aloisio, F. Alonso, C. Alpigiani, M. Alvarez Estevez, A. Álvarez Fernández, M. G. Alviggi, M. Aly, Yara Do Amaral Coutinho, A. Ambler, Christoph Amelung, M. Amerl, Christoph Ames, D. Amidei, S. P. Amor Dos Santos, K. R. Amos, V. Ananiev, Christos 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, D. J. A. Antrim, F. Anulli, M. Aoki, T. Aoki, J. A. Aparisi Pozo, M. A. Aparo
Abstract
Abstract A search for heavy right-handed Majorana or Dirac neutrinos $$N_{\textrm{R}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>N</mml:mi> <mml:mtext>R</mml:mtext> </mml:msub> </mml:math> and heavy right-handed gauge bosons $$W_{\textrm{R}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>W</mml:mi> <mml:mtext>R</mml:mtext> </mml:msub> </mml:math> is performed in events with energetic electrons or muons, with the same or opposite electric charge, and energetic jets. The search is carried out separately for topologies of clearly separated final-state products (“resolved” channel) and topologies with boosted final states with hadronic and/or leptonic products partially overlapping and reconstructed as a large-radius jet (“boosted” channel). The events are selected from pp collision data at the LHC with an integrated luminosity of 139 fb $$^{-1}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mrow/> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:math> collected by the ATLAS detector at $$\sqrt{s} = 13$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> <mml:mo>=</mml:mo> <mml:mn>13</mml:mn> </mml:mrow> </mml:math> TeV. No significant deviations from the Standard Model predictions are observed. The results are interpreted within the theoretical framework of a left-right symmetric model, and lower limits are set on masses in the heavy right-handed $$W_{\textrm{R}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>W</mml:mi> <mml:mtext>R</mml:mtext> </mml:msub> </mml:math> boson and $$N_{\textrm{R}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>N</mml:mi> <mml:mtext>R</mml:mtext> </mml:msub> </mml:math> plane. The excluded region extends to about $$m(W_{\textrm{R}}) = 6.4$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>m</mml:mi> <mml:mo>(</mml:mo> <mml:msub> <mml:mi>W</mml:mi> <mml:mtext>R</mml:mtext> </mml:msub> <mml:mo>)</mml:mo> <mml:mo>=</mml:mo> <mml:mn>6.4</mml:mn> </mml:mrow> </mml:math> TeV for both Majorana and Dirac $$N_{\textrm{R}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>N</mml:mi> <mml:mtext>R</mml:mtext> </mml:msub> </mml:math> neutrinos at $$m(N_{\textrm{R}})<1$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>m</mml:mi> <mml:mo>(</mml:mo> <mml:msub> <mml:mi>N</mml:mi> <mml:mtext>R</mml:mtext> </mml:msub> <mml:mo>)</mml:mo> <mml:mo><</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:math> TeV. $$N_{\textrm{R}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>N</mml:mi> <mml:mtext>R</mml:mtext> </mml:msub> </mml:math> with masses of less than 3.5 (3.6) TeV are excluded in the electron (muon) channel at $$m(W_{\textrm{R}})=4.8$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>m</mml:mi> <mml:mo>(</mml:mo> <mml:msub> <mml:mi>W</mml:mi> <mml:mtext>R</mml:mtext> </mml:msub> <mml:mo>)</mml:mo> <mml:mo>=</mml:mo> <mml:mn>4.8</mml:mn> </mml:mrow> </mml:math> TeV for the Majorana neutrinos, and limits of $$m(N_{\textrm{R}})$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>m</mml:mi> <mml:mo>(</mml:mo> <mml:msub> <mml:mi>N</mml:mi> <mml:mtext>R</mml:mtext> </mml:msub> <mml:mo>)</mml:mo> </mml:mrow> </mml:math> up to 3.6 TeV for $$m(W_{\textrm{R}}) = 5.2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>m</mml:mi> <mml:mo>(</mml:mo> <mml:msub> <mml:mi>W</mml:mi> <mml:mtext>R</mml:mtext> </mml:msub> <mml:mo>)</mml:mo> <mml:mo>=</mml:mo> <mml:mn>5.2</mml:mn> </mml:mrow> </mml:math> (5.0) TeV in the electron (muon) channel are set for the Dirac neutrinos. These constitute the most stringent exclusion limits to date for the model considered.