Single top quark production as a probe of anomalous tqγ and tqZ couplings at the FCC-ee

Hamzeh Khanpour (Department of Physics, University of Science and Technology of Mazandaran, P.O. Box 48518-78195, Behshahr, Iran; School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran, Iran) ; Sara Khatibi (School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran, Iran) ; Morteza Khatiri Yanehsari (School of Physics, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran, Iran) ; Mojtaba Mohammadi Najafabadi (School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran, Iran)

In this paper, a detailed study to probe the top quark Flavour-Changing Neutral Currents (FCNC) tqγ and tqZ at the future e−e+ collider FCC-ee in two different center-of-mass energies of 240 and 350 GeV is presented. A set of useful variables are proposed and used in a multivariate technique to separate signal e−e+→Z/γ→tq¯ (t¯q) from Standard Model background processes. The study includes a fast detector simulation based on the delphes package to consider the detector effects. The upper limits on the FCNC branching ratios at 95% confidence level (CL) in terms of the integrated luminosity are presented. It is shown that with 300 fb−1 of integrated luminosity of data, FCC-ee would be able to exclude the effective coupling strengths above O(10−4−10−5) which is corresponding to branching fraction of O(0.01−0.001) %. We show that moving to a high-luminosity regime leads to a significant improvement on the upper bounds on the top quark FCNC couplings to a photon or a Z boson.

{
  "license": [
    {
      "url": "http://creativecommons.org/licenses/by/3.0/", 
      "license": "CC-BY-3.0"
    }
  ], 
  "copyright": [
    {
      "statement": "The Author(s)"
    }
  ], 
  "control_number": "22052", 
  "_oai": {
    "updated": "2018-04-18T13:01:21Z", 
    "id": "oai:repo.scoap3.org:22052", 
    "sets": [
      "PLB"
    ]
  }, 
  "authors": [
    {
      "surname": "Khanpour", 
      "given_names": "Hamzeh", 
      "raw_name": "Khanpour, Hamzeh", 
      "affiliations": [
        {
          "country": "Iran", 
          "value": "Department of Physics, University of Science and Technology of Mazandaran, P.O. Box 48518-78195, Behshahr, Iran"
        }, 
        {
          "country": "Iran", 
          "value": "School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran, Iran"
        }
      ], 
      "full_name": "Khanpour, Hamzeh", 
      "orcid": "0000-0001-7078-7177"
    }, 
    {
      "raw_name": "Khatibi, Sara", 
      "affiliations": [
        {
          "country": "Iran", 
          "value": "School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran, Iran"
        }
      ], 
      "surname": "Khatibi", 
      "given_names": "Sara", 
      "full_name": "Khatibi, Sara"
    }, 
    {
      "raw_name": "Yanehsari, Morteza Khatiri", 
      "affiliations": [
        {
          "country": "Iran", 
          "value": "School of Physics, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran, Iran"
        }
      ], 
      "surname": "Yanehsari", 
      "given_names": "Morteza Khatiri", 
      "full_name": "Yanehsari, Morteza Khatiri"
    }, 
    {
      "raw_name": "Najafabadi, Mojtaba Mohammadi", 
      "affiliations": [
        {
          "country": "Iran", 
          "value": "School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran, Iran"
        }
      ], 
      "surname": "Najafabadi", 
      "given_names": "Mojtaba Mohammadi", 
      "full_name": "Najafabadi, Mojtaba Mohammadi"
    }
  ], 
  "_files": [
    {
      "checksum": "md5:9fb1c6a0d0bf662e9c76e404d376a9fd", 
      "filetype": "xml", 
      "bucket": "06c888dc-9dae-4d0b-bc68-3c76d099a855", 
      "version_id": "a3ce6bf7-3448-483a-9ead-542241416944", 
      "key": "10.1016/j.physletb.2017.10.047.xml", 
      "size": 204180
    }, 
    {
      "checksum": "md5:c0997efa4e5b4786a1ca34b9d7fbe467", 
      "filetype": "pdf", 
      "bucket": "06c888dc-9dae-4d0b-bc68-3c76d099a855", 
      "version_id": "89f7106b-91db-4e5c-b52d-1cb3d8865a4c", 
      "key": "10.1016/j.physletb.2017.10.047.pdf", 
      "size": 950006
    }, 
    {
      "checksum": "md5:015ff72ed598e4841b2ed9c125654c2d", 
      "filetype": "pdf/a", 
      "bucket": "06c888dc-9dae-4d0b-bc68-3c76d099a855", 
      "version_id": "1a2afb66-7977-405a-a349-56c6b3a63e04", 
      "key": "10.1016/j.physletb.2017.10.047_a.pdf", 
      "size": 1283771
    }
  ], 
  "record_creation_date": "2017-10-25T00:00:00", 
  "titles": [
    {
      "source": "Elsevier", 
      "title": "Single top quark production as a probe of anomalous tq\u03b3 and tqZ couplings at the FCC-ee"
    }
  ], 
  "dois": [
    {
      "value": "10.1016/j.physletb.2017.10.047"
    }
  ], 
  "publication_info": [
    {
      "journal_title": "Physics Letters B", 
      "material": "article", 
      "year": 2017
    }
  ], 
  "$schema": "http://repo.scoap3.org/schemas/hep.json", 
  "abstracts": [
    {
      "source": "Elsevier", 
      "value": "In this paper, a detailed study to probe the top quark Flavour-Changing Neutral Currents (FCNC) tq\u00ce\u00b3 and tqZ at the future e\u00e2\u0088\u0092e+ collider FCC-ee in two different center-of-mass energies of 240 and 350 GeV is presented. A set of useful variables are proposed and used in a multivariate technique to separate signal e\u00e2\u0088\u0092e+\u00e2\u0086\u0092Z/\u00ce\u00b3\u00e2\u0086\u0092tq\u00c2\u00af\u00c2 (t\u00c2\u00afq) from Standard Model background processes. The study includes a fast detector simulation based on the delphes package to consider the detector effects. The upper limits on the FCNC branching ratios at 95% confidence level (CL) in terms of the integrated luminosity are presented. It is shown that with 300\u00c2 fb\u00e2\u0088\u00921 of integrated luminosity of data, FCC-ee would be able to exclude the effective coupling strengths above O(10\u00e2\u0088\u00924\u00e2\u0088\u009210\u00e2\u0088\u00925) which is corresponding to branching fraction of O(0.01\u00e2\u0088\u00920.001) %. We show that moving to a high-luminosity regime leads to a significant improvement on the upper bounds on the top quark FCNC couplings to a photon or a Z boson."
    }
  ], 
  "imprints": [
    {
      "date": "2017-10-27", 
      "publisher": "Elsevier"
    }
  ], 
  "acquisition_source": {
    "date": "2017-10-25T00:00:00", 
    "source": "Elsevier", 
    "method": "scoap3", 
    "submission_number": "372790d4430511e898b102163e01809a"
  }
}
Published on:
27 October 2017
Publisher:
Elsevier
Published in:
Physics Letters B (2017)

DOI:
https://doi.org/10.1016/j.physletb.2017.10.047
Copyrights:
The Author(s)
Licence:
CC-BY-3.0

Fulltext files: