Musings

Staring at the Tea Leaves

LEP closed down in 2000, to make way for the LHC. There were, towards the end, intriguing hints that there was, perhaps, a bit of a bump in the number of b-jet events, indicating the possibility of a Higgs. Arguments were made that the LEP run should be extended. But, in the end, LEP was shut down on schedule, and the consensus was that it had established a lower limit of $m_h \gt 115$ GeV.

Still, people continue to pore over the data and, recently, Dermisek and Gunion have challenged the above consensus. The limit seems to be rather neatly evaded in the NMSSM¹. Rather than the dominant decay being $h\to b\overline{b}$, one expects the dominant decay mode to be $h\to a a$, where $a$ is a CP-odd boson of mass, $m_a\sim 30-40$ GeV. The $a$ subsequently decays, $a\to b\overline{b}$. The upshot is that, rather than a big excess of two b-jet events, from $Z h\to Z b\overline{b}$, we expect smaller excesses of both two b-jet and four b-jet events (from $Z h\to Z a a \to Z b\overline{b}b\overline{b}$). That, according to Dermisek and Gunion, is what’s seen in the LEP data, and is consistent with $m_h\sim 105$ GeV.

If correct, that’s very bad news for direct detection of the Higgs at the LHC. [As I emphasize to Sean, below we’ll see other stuff, just not a Higgs.]