Search for heavy resonances decaying into a pair of Z bosons in the $$\ell ^+\ell ^-\ell '^+\ell '^-$$ and $$\ell ^+\ell ^-\nu {{\bar{\nu }}}$$ final states using 139 $$\mathrm {fb}^{-1}$$ of proton–proton collisions at $$\sqrt{s} = 13\,$$TeV with the ATLAS detector

Aad, G; Abbott, B; Abbott, DC; Abud, AA; Abeling, K; Abhayasinghe, DK; Abidi, SH; AbouZeid, OS; Abraham, NL; Abramowicz, H; Abreu, H; Abulaiti, Y; Acharya, BS; Achkar, B; Adam, L; Bourdarios, CA; Adamczyk, L; Adamek, L; Adelman, J; Adiguzel, A; Adorni, S; Adye, T; Affolder, AA; Afik, Y; Agapopoulou, C; Balunas, WK; Bortoletto, D; Cooper-Sarkar, AM; Ferrando, J; Frost, JA; Gallas, EJ; Gwenlan, C; Hays, CP; Iizawa, T; Merlassino, C; Mermod, P; Moser, B; Nagai, K; Nickerson, RB; Potamianos, K; Rossi, E; Schopf, E; Shipsey, IPJ; Viehhauser, GHA; Weidberg, AR

Journal article

Search for heavy resonances decaying into a pair of Z bosons in the $$\ell ^+\ell ^-\ell '^+\ell '^-$$ and $$\ell ^+\ell ^-\nu {{\bar{\nu }}}$$ final states using 139 $$\mathrm {fb}^{-1}$$ of proton–proton collisions at $$\sqrt{s} = 13\,$$TeV with the ATLAS detector

Abstract:: It has been proposed that, beside the known resonance with mass $m_h=$ 125 GeV, the Higgs field might exhibit a second resonance with a larger mass $(M_H)^{\rm Theor} = 690 \pm 10 ~({\rm stat}) \pm 20 ~({\rm sys})$ GeV which, however, would couple to longitudinal W's with the same typical strength as the low-mass state at $125$ GeV and thus represent a relatively narrow resonance. Looking for evidences in the LHC data, from two analyses published in 2021 by ATLAS (searching for heavy resonances decaying into final states with 4 charged leptons or with photon pairs) we have found combined indications for a new resonance of mass $(M_H)^{\rm Exp} \sim $ 680 (15) GeV and total width $(\Gamma_H)^{\rm Exp} \sim$ 45 (15) GeV. More recent results by CMS (searching for heavy resonances decaying into a pair of h(125) Higgs bosons or looking for high-mass photon pairs produced in pp-diffractive scattering) also show definite excesses pointing toward a new resonance of mass $(M_H)^{\rm Exp} \sim$ 660(30) GeV. However, beside the agreement with the predicted mass range, a clean indication derives from the ATLAS 4-lepton data which reproduce to high accuracy the expected correlation between resonating peak cross section $\sigma_R(pp\to H \to 4l)$ and the ratio $\gamma_H=\Gamma_H/M_H$. This correlation is mainly determined by the lower mass $m_h=$ 125 GeV and supports the view that the known $m_h$ and the new heavy resonance are two different excitations of the same Higgs field by effectively eliminating the spin-zero vs. spin-2 ambiguity in the interpretation of the heavy state. The overall statistical evidence might now be above the traditional 5-sigma discovery threshold because, when comparing with a definite theoretical prediction as in our case, local excesses should maintain intact their statistical significance and not be downgraded by the so called "look-elsewhere" effect.Comment: 14 pages, 4 figures, 4 table

Publication status:: Published

Peer review status:: Peer reviewed

Actions

Email

Email this record

Send the bibliographic details of this record to your email address.

Your Email
Please enter the email address that the record information will be sent to.

-
Your message (optional)
Please add any additional information to be included within the email.
Share
Cite

Cite this record

APA Style

Aad, G., Abbott, B., Abbott, D. C., Abud, A. A., Abeling, K., Abhayasinghe, D. K., Abidi, S. H., AbouZeid, O. S., Abraham, N. L., Abramowicz, H., Abreu, H., Abulaiti, Y., Acharya, B. S., Achkar, B., Adam, L., Bourdarios, C. A., Adamczyk, L., Adamek, L., Adelman, J., … Weidberg, A. R. (2021). Search for heavy resonances decaying into a pair of Z bosons in the $$\ell ^+\ell ^-\ell '^+\ell '^-$$ and $$\ell ^+\ell ^-\nu {{\bar{\nu }}}$$ final states using 139 $$\mathrm {fb}^{-1}$$ of proton–proton collisions at $$\sqrt{s} = 13\,$$TeV with the ATLAS detector. The European Physical Journal C, 81(4), 332.

MLA Style

Aad, G, et al. “Search for Heavy Resonances Decaying into a Pair of Z Bosons in the $$\Ell ^+\Ell ^-\Ell '^+\Ell '^-$$ and $$\Ell ^+\Ell ^-\Nu {{\Bar{\Nu }}}$$ Final States Using 139 $$\Mathrm {Fb}^{-1}$$ of Proton–Proton Collisions at $$\Sqrt{s} = 13\,$$TeV with the ATLAS Detector.” The European Physical Journal C, vol. 81, no. 4, 2021, p. 332.

Chicago Style

Aad, G, B Abbott, DC Abbott, et al. 2021. “Search for Heavy Resonances Decaying into a Pair of Z Bosons in the $$\Ell ^+\Ell ^-\Ell '^+\Ell '^-$$ and $$\Ell ^+\Ell ^-\Nu {{\Bar{\Nu }}}$$ Final States Using 139 $$\Mathrm {Fb}^{-1}$$ of Proton–Proton Collisions at $$\Sqrt{s} = 13\,$$TeV with the ATLAS Detector.” The European Physical Journal C 81 (4): 332.
Print