The Z' Bill Marciano has been talking about, has a mass that is unbound on the low energy side, i.e. they are dark Z's as Niels is saying. This Z' has not only too little coupling to be produced in LHCb, but also has too little mass to decay in anything LHCb could detect with confidence. However, these Z's do modify the weak mixing angle at low energy. Curious to hear whether these will be addressed as well. Cheers, Hans.
On 5/1/2015 9:16 AM, Niels Tuning wrote:
Hi Suvayu,
This Z' (ie. one that is discussed in the context of B0->K*mumu) would be different from a Z in that it would couple weaker to quarks than to leptons. As a result, one would produce few of them directly in a hadron collider, unfortunately...
(As far as I understood...) Cheers, Niels
On Fri, 1 May 2015, Marcel Merk wrote:
Hi Suvayu, et al, Indeed, the Z' is hot recently as it can be related to signatures of B_s,d --> mumu, B-->K*mumu, and R_K=(B->Kmumu/B->Kee). As was discussed in Moriond, all of these measurements are being fitted with a modified C9 Wilson coefficient, which would then perhaps point to New Physics of a Z' (or leptoquarks, or perhaps even many other things). In fact, we made a public news item on this on the Nikhef website on March 20,
In order to be consistent with other measuremnts, the mass range of such a Z' would be in the range of 2 - 7 TeV or so. Also its couplings should be non-standard, in particular to describe the lepton flavour vioalting R_K ratio.
There are two events coming up:
- Jan-Willen van Holten from Nikhef-theory is going to discuss the
theory aspects of the Z', as he was asked by the NIkhef theory community who triggered on the Z' news. (see Jan Willem announcement) 2. Altmannshofer (one of the speakers presenting the Z' results at Moriond) will come to Nikhef for a colloquium on the friday after our workshop. We are thinking to organise a little workshop with Robert around this talk.
cheers,
- Marcel
On 1 May 2015 at 00:49, Suvayu Ali ali.suvayu@nikhef.nl wrote: Hi Marcel, others, and Z' aficionados,
I have a question that keeps puzzling me. Am I correct in noticing a sudden increased interest on Z' models? This puzzles me since I was under the impression these models have been excluded to almost 3TeV by direct searches! See: http://arxiv.org/abs/1405.4123 (assuming SM couplings). In fact, the limits were already past 1 TeV back in 2011! Do these results somehow not apply to some LHCb results (e.g. Bs → μμ)? If so, why? Are there other motivations than significantly weaker couplings for them to not show up in direct searches? Just a few itches I had to scratch ... Cheers, PS: Do we also have a page like this?https://twiki.cern.ch/twiki/bin/view/AtlasPublic/ExoticsPublicResults
On Thu, Apr 30, 2015 at 11:22:04PM +0200, Marcel Merk wrote: > Dear bfys friends, > > You are all very welcome to join the informal lecture of Jan Willem on Z' > physics and the connection to right handed neutrino's.... > > ---------- Forwarded message ---------- > From: Jan-Willem van Holten <jwvholten@gmail.com> > Date: 30 April 2015 at 13:32 > Subject: Z' lecture > To: theory-wide@nikhef.nl, Marcel Merk <marcel.merk@nikhef.nl>, Bob van > Eijk <vaneijk@nikhef.nl> > > > Dear colleagues, > > at the request of some of our PhD/master students I will arrange an > informal lecture/discussion session on > Completing the standard model with right-handed neutrinos and Z' > > Time: Monday May 11, 14.00-16.00 (or how long it takes) > Place: H331 > > Everyone interested is welcome, basic knowledge of QFT theory and the > standard model will be assumed. > > Jan-Willem > > > > -- > Prof.dr. J.W. van Holten > > Theoretical Physics > Nikhef, Amsterdam > and Leiden University > Netherlands
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