Synopsis

No Hint of Exotic Higgs Particles

Physics 8, s44
An analysis of data from the now-shuttered Tevatron excludes certain Higgs bosons with exotic properties.

In 2012, the ATLAS and CMS collaborations at the Large Hadron Collider (LHC) in Geneva discovered a Higgs boson that was consistent with the standard model of particle physics. However, some theories propose that other Higgs-like particles with different properties may exist alongside the standard model Higgs. A new analysis of data from Fermilab’s Tevatron outside of Chicago sets limits on some of these “exotic Higgs” particles.

The standard model predicts that the Higgs boson is a scalar particle, which means it has zero spin and even parity (describing how it behaves in a mirror reflection). The Higgs discovered at the LHC is a scalar particle, as verified in data where the particle decays into other bosons (W and Z bosons, as well as photons). It’s still possible, however, that an exotic Higgs boson of similar mass exists but decays preferentially through other channels.

The Tevatron, which shut down in 2011, studied proton-antiproton collisions at energies of $1.96$ tera-electron-volts, about a factor of $4$ below the LHC’s collision energy in 2012. In spite of this, the two Tevatron-based experiments, CDF and D0, uncovered evidence in 2012 of a Higgs boson decaying into fermions, specifically, a pair of bottom quarks. The two collaborations have again combined their data to check for exoticness in this fermion decay channel. The Tevatron data show no signal consistent with a Higgs boson having spin zero and odd parity (a so-called pseudoscalar) or spin $2$ and even parity (gravitonlike). The results are important for building the case that the Higgs boson seen in particle colliders is indeed the standard model Higgs.

This research is published in Physical Review Letters.

–Michael Schirber

Subject Areas

Particles and Fields

Related Articles

Particles and Fields

Muon’s Escalating Challenge to the Standard Model

Measurements of the muon magnetic moment strengthen a previously reported tension with theoretical predictions, ushering in a new era of precision tests of the standard model. Read More »

Particles and Fields

A New View of the Universe’s Dark Side

The Dark Energy Survey Collaboration has updated a model of the Universe to correctly capture more galaxy measurements. Read More »

Particles and Fields

Using Fluctuations to Measure Beam Properties

A new way of measuring a vital property of electron beams helps prepare researchers for next-generation synchrotron light sources. Read More »