Friday, 29 May 2015

Planck 2015 Liveblog: Day Five, Session Three

The final session (not counting the summary talk) of the conference.

3:00 pm: "Searches Strategies for Heavy Quark Partners at LHC run-II", Thomas Flacke

Number of quark partners, depending of course on the fermion embedding.  Production can be divided into QCD pair production and various EW single production channels.  Their decay signals vary; some types have a single dominant decay, but the possibility of decays to bW, tZ and th in differnt regions of parameter space make a top-like top partner more interesting.

Classic exclusions from run-I based on pair production (less model-dependent).  Some single-production bounds from ATLAS (only).

At run II, single production will be relatively more important simply on kinematic grounds.  Additionally, boosted decay products (and hence the use of jet substructure) become relevant.

Some projected exclusion contours that look both reasonable and good. Limits could go up to 1 or 2 TeV, depending no the type of top partner.

3:50 pm: "How to Avoid Unnatural Hierarchical Thermal Leptogenesis", Jackson Clarke

Hierarchical Leptogenesis in Type I See-Saw is unnatural.  This is because the CP asymmetry, needed for leptogenesis, is proportional to the right-handed neutrino Yukawas.  Demanding that the loop corrections to the Higgs be below 1 TeV gives an upper bound on the NR mass of 3 x 107 GeV.  This is to be compared to the standard lower bound for leptogenesis, 108 GeV.

Original calculation was done in 1-flavour model.  Do things vary in 3-flavour model?  Get some benefits from mixing matrix, but it turns out that the constraint remains.

To solve this, move to a 2HDM where second Higgs couples to right-handed neutrinos.  This has a small VEV, which turns out to avoid the naturalness and leptogenesis bounds.  Some model-building to see if things can work.  Example here involves softly breaking Z2 together with a large, positive mass parameter for the second Higgs.

Various constraints (flavour, avoiding reintroducing fine tuning).  Notable one is the vacuum stability; need theory to remain under control at least to the see-saw scale.

4:00 pm: "Stabilizing the Higgs potential with a Z'", Venus Keus

Restrict ourselves to a heavy Z', 3 TeV, above even the current SSM constraints.  Running is not trivial now due to mixings of states, both vector kinetic mixing and also mixing involving dark Higgses or fermions.  Work is done in a highly general basis, allowing range of charges for SM fields.

Get extra, positive combination to running of Higgs quartic.  Also get extra negative contribution to top Yukawa.

Find regions in parameter space where Higgs potential is absolutely stable.  Reasonable chunks of parameter space.  Interestingly, if Z' can be light (leptophobic, 200 GeV) can get stable potential even if Higgs is not directly charged under the new U(1).

What about Yukawas with dark scalars?  Assumed small.
What of future constraints?  Will make things worse.

4:15 pm: "One loop corrections to the Higgs EW chiral Lagrangian", J.J. Sanz-Cillero

Non-linear Higgs EFT: computed UV divergences at NLO.  Consider the "κ framework" of coupling deviations from the SM.  This is fine for low precision, but need to use EFTs to handle precision data.

Planck 2015 Liveblog: Day Five, Session Two

The first of two parallel sessions, I'll be splitting my time between DM and SUSY.

Planck 2015 Liveblog: Day Five Session One

We come to the final day of the conference, and perhaps the most interesting one based on the talk titles.  We have one plenary session, not counting the conference summary.

Planck 2015 Liveblog: Day Four, Session Four

The final session of today is, again, devoted to parallel talks.  I will once again switch between the SUSY and DM sessions.

Thursday, 28 May 2015

Planck 2015 Liveblog: Day Four, Session Three

I skipped the morning sessions with almost no regret.  (Actually, there was a talk from LHCb among all the string theory, that might have been interesting to attend.)  Thankfully, there are two talks in the last plenary session of the day that should be interesting.

Wednesday, 27 May 2015

Planck 2015 Liveblog: Day Three Session Three

Today was the day of the conference excursion, to the Dodona archeological site/amphitheatre.  So we have only three sets of talks, finishing with the second set of parallel talks.  Thanks to the excursion, we're back on schedule, more or less, and I'm going to try changing sessions after three talks.

Planck 2015 Liveblog: Day Three Session Two

The second session today is ahead of the curve, with two talks I'm somewhat interested in.  Unfortunately the exception is the middle talk.  We are, of course, almost 30 minutes over time.

Planck 2015 Liveblog: Day Three Session One

Day three starts with a slightly odd session (for me); one talk I am interested in followed by three I am not.  I didn't finish writing my own talk yesterday, so I guess that works out for me.

Plank 2015 Liveblog: Day Two Session Four

The final session of the day is the first parallel session of the conference.  According to the conference timetable, the first talk was supposed to be at 5pm.  Even if we hadn't been running late, that would have left us with no time for the coffee break; or to put it another way, the schedule had an error.  Which isn't exactly a surprise for thie conference.  As it is, it looks like this session will start at 5:40pm, and so probably not finish till 8.

Given how bad timekeeping has been at this conference, I'll mostly stay in this session.  There is one talk at the end of another session I want to attend, though.

Tuesday, 26 May 2015

Planck 2015 Liveblog: Day Two Session Three

The first session after lunch looks pretty dull too.  Also, we are already starting five minutes later.

Planck 2015 Liveblog: Day Two Session Two

We progress to the second day of the conference.  I decided to skip the first session of the morning, as none of the talks interested me and I'm still writing my talk.  The second session, however, has some stuff on neutrinos and unification that could be interesting.

Planck 2015 Liveblog: Day One, Session Four

The final session of the first day is back to technical subjects.

Monday, 25 May 2015

Planck 2015 Liveblog: Day One, Session Three

The first session after lunch is very neutrino-focused.

Planck 2015 Liveblog: Day One, Session Two

Refreshed by two coffees, and learning that lunch has been paid for, we start the second session of the conference.  This set of talks is very SUSY-focused.

Planck 2015 Liveblog: Day One, Session One

So Planck starts today, with a day full of plenary talks.  It looks like a fairly technical slate, too, but on the other hand I got a good night's sleep last night so I might be able to stay awake.  I could do with another cup of coffee, but that's always true.

Sunday, 24 May 2015

Good News from Ireland!

I'm still planning to write my second response to the UK election, hopefully before Planck starts on Monday.  But before I do, I had to note the fantastic result from Ireland, which has become the first country ever to legalise gay marriage by popular vote.  And not by a small margin, either; over 60% voted for equality.  It's a wonderful result, and a sign of the changing times.  Congratulations to all who campaigned on the right side!

Sunday, 10 May 2015

UK General Election Results I: The Parties

The results of the UK election are in, and generally not what I was hoping.  Like basically everyone who had followed the polls, the final results surprised me.  But putting that aside, I have a lot of thoughts on the outcome, and what is a blog but a place for your opinions?  Like my pre-election thoughts, I have enough to say that I'm splitting everything into two posts.  Here, I'll talk about things solely in terms of the impact on parties.  My policy-related opinions will follow later.

Thursday, 7 May 2015

UK Election: The Good and the Bad

My previous post was getting quite large, so I've split off my opinions about some election things.

UK General Election: Thoughts on the Outcome

Tomorrow will see the UK general election, with results declared through the night.  I will miss the election, both in that I'll be flying across the Atlantic while votes are counted, and in that I'm not registered anywhere in the UK.   At this point, having lived abroad for over a decade, I don't think I can be.  Given that my parent's district is quite competitive this year, that's somewhat unfortunate.

I haven't written anything on the election campaign because I've been busy with work, travel and talk writing.  But I've certainly been keeping an eye on things, and I do have a few opinions I'd like to commit to paper (or the internet).  This post has gotten so long, I've decided to split it.  First, let's discuss what we are likely to see come Friday morning.

Phenomenology 2015 Overview

So ends my sixth Pheno conference.  It was fun, on the whole.  I didn't learn anything too groundbreaking, but to be fair I didn't expect to.  There were some good talks, some bad talks, and friends old and new.  One thing that did hit me was how old it all made me feel.  Pheno is a great conference for grad students and young postdocs, but that descriptor hardly applies to me any more.  So I might very well not return next year, and go to other conferences instead.

Pheno 2015 Liveblog: Day 3 Session 2

Last night was the conference banquet, and unfortunately as a consequence I missed the first session this morning.  So we come to the final session of the conference, which is both reflective of the current status and also looking to the future.

Wednesday, 6 May 2015

Pheno 2015 Liveblog: Day 2 Session 4

And, already, we come to the last parallel session of the conference.  I am once again bouncing around sessions.

Pheno 2015 Liveblog: Day 2 Session 3

I've decided to spend the first session after lunch today in a single session, Dark Matter III.  It will if nothing else let me charge my laptop.

Pheno 2015 Liveblog: Day 2 Session 2

The second session of the day is the dark matter session.  I'm looking forward to it!

Tuesday, 5 May 2015

Pheno 2015 Liveblog: Day 2 Session 1

We start the second day of Pheno 2015 with some talks on flavour physics and QCD.

Pheno 2015 Liveblog Day 1 Session 4

For the last session of the day, I'm staying in one place - the Higgs II session.

Pheno 2015 Liveblog Day 1 Session 3

First parallel session, I'll be moving around a bit.  I'll start in Higgs I.

Pheno 2015 Liveblog: Day 1 Session 2

We return, refreshed from some good coffee (by which I mean it existed and contained caffeine) for the second session of the day.  Though someone stole my seat.  This session contains another Higgs talk, followed by a couple of cosmology/dark matter ones.

Monday, 4 May 2015

Phenomenology 2015 Liveblog: Day 1 Session 1

If there's one thing that gets me to blog every year, it's attending a conference.  I'm again at Phenomenology, the sixth year I've been here.  As usual, we start with some experimental talks; these are pretty much standard reviews.  No new results are going to be announced here, and as everyone well understands we've only found SM stuff so far.