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Posts Tagged ‘p5’

I know that the majority of the posts I’ve written have focused on physics issues and results, specifically those related to LHCb. I’d like to take this opportunity, however, to focus on the development of the field of High Energy Physics (HEP) and beyond.

As some of you know, in 2013, we witnessed an effectively year-long conversation about the state of our field, called Snowmass. This process is meant to collect scientists in the field, young and old alike, and ask them what the pressing issues for the development of our field are. In essence, it’s a “hey, stop working on your analysis for a second and let’s talk about the big issues” meeting. They came out with a comprehensive list of questions and also a bunch of working papers about the discussions. If you’re interested, go look at the website. The process was separated into “frontiers,” or groups that the US funding agencies put together to divide the field into the groups that they saw fit. I’ll keep my personal views on the “frontiers” language for a different day, and instead share a much more apt interpretation of the frontiers, which emerged from Jonathan Asaadi, of Snowmass Young and Quantum Diaries. He emphasizes that we are coming together to tackle the biggest problems as a team, as opposed to dividing into groups, illustrated as Voltron in his slide below.


Slide from presentation of Jonathan Asaadi at the USLUO (now USLUA) 2013 annual meeting in Madison, Wisconsin. The point here is collaboration between frontiers to solve the biggest problems, rather than division into separate groups.

And that’s just what happened. While I willingly admit that I had zero involvement in this process aside from taking the Snowmass Young survey, I still agree with the conclusions which were reached about what the future of our field should look like. Again, I highly encourage you to go look at the outcome.

Usually, this would be the end of the story, but this year, the recommendations from Snowmass were passed to a group called P5 (Particle Physics Project Prioritization Panel). The point of this panel was to review the findings of Snowmass and come up with a larger plan about how the future of HEP will proceed. The big ideas had effectively been gathered, now the hard questions about which projects can pursue these questions effectively are being asked. This specifically focuses on what the game plan will be for HEP over the next 10-20 years, and identifies the distinct physics reach in a variety of budget situations. Their recommendation will be passed to HEPAP (High Energy Physics Advisory Panel), which reviews the findings, then passes its recommendation to the US government and funding agencies. The P5 findings will be presented to HEPAP  on May 22nd, 2014 at 10 AM, EST. I invite you to listen to the presentation live here. The preliminary executive report and white paper can be found after 10 EST on the 22nd of May on the same site, as I understand.

This is a big deal.

There are two main points here. First, 10-20 years is a long time, and any sort of recommendation about the future of the field over such a long period will be a hard one. P5 has gone through the hard numbers under many different budget scenarios to maximize the science reach that the US is capable of. Looking at the larger political picture, in 2013, the US also entered the Sequester, which cut spending across the board and had wide implications for not only the US but worldwide. This is a testament to the tight budget constraints that we are working in now, and will most certainly face in the future. Even considering such a process as P5 shows that the HEP community recognizes this point, and understands that without well defined goals and tough considerations of how to achieve them, we will endanger the future funding of any project in the US or with US involvement.

Without this process, we will endanger future funding of US HEP.

We can take this one step further with a bit more concrete example. The majority of HEP workings are done through international collaboration, both experiment and theory alike. If any member of such a collaboration does not pull their weight, it puts the entire project into jeopardy. Take, for example, the US ATLAS and CMS programs, which have 23% and 33% involvement from the US, respectively, in both analysis and detector R&D. If these projects were cut drastically over the next years, there would have to be a massive rethinking about the strategies of their upgrades, not to mention possible lack of manpower. Not only would this delay one of the goals outlined by Snowmass, to use the Higgs as a discovery tool, but would also put into question the role of the US in the future of HEP. This is a simple example, but is not outside the realm of possibility.

The second point is how to make sure a situation like this does not happen.

I cannot say that communication of the importance of this process has been stellar. A quick google search yields no mainstream news articles about the process, nor the impact. In my opinion, this is a travesty and that’s the reason why I am writing this post. Symmetry Magazine also, just today, came out with an article about the process. Young members of our community who were not necessarily involved in Snowmass, but seem to know about Snowmass, do not really know about P5 or HEPAP. I may be wrong, but I draw this conclusion from a number of conversations I’ve had at CERN with US postdocs and students. Nonetheless, people are quite adamant about making sure that the US does continue to play a role in the future of HEP. This is true across HEP, the funding agencies and the members of Congress. (I can say this as I went on a trip with the USLUO, FNAL and SLAC representatives to lobby congress on behalf of HEP in March of this year, and this is the sentiment which I received.) So the first step is informing the public about what we’re doing and why.

The stuff we do is really cool! We’re all organized around how to solve the biggest issues facing physics! Getting the word out about this is key.

Go talk to your neighbor!

Go talk to your local physicist!

Go talk to your congressperson!

Just talk about physics! Talk about why it excites you and talk about why it’s interesting to explore! Maybe leave out the CLs plots, though. If you didn’t know, there’s also a whole mess of things that HEP is good for besides colliding particles! See this site for a few.

The final step is understanding the process. The biggest worry I have is what happens after HEPAP reviews the P5 recommendations. We, as a community, have to be willing to endure the pains of this process. Good science will be excluded. However, there are not infinite funds, nor was a guarantee of funding ever given. Recognition of this, while focusing on the big problems at hand and thinking about how to work within the means allowed is *the point* of the conversation. The better question is, will we emerge from the process unified or split? Will we get behind the Snowmass process and answer the questions posed to us, or fight about how to answer them? I certainly hope the answer is that we will unify, as we unified for Snowmass.

An allegorical example is from a slide from Nima Arkani-Hamed at Pheno2014, shown in the picture.

One slide from Nima Arkani-Hamed's presentation at Pheno2014

One slide from Nima Arkani-Hamed’s presentation at Pheno2014


The take home point is this: If we went through the exercise of Snowmass, and cannot pull our efforts together to the wishes of the community, are we going to survive? I would prefer to ask a different question: Will we not, as a community, take the opportunity to answer the biggest questions facing physics today?

We’ll see on the 22nd and beyond.



Update: May 27, 2014


As posted in the comments, the full report can be found here, the presentation given by Steve Ritz, chair of P5 can be found here, and the full P5 report can be found here.  Additionally, Symmetry Magazine has a very nice piece on the report itself. As they state in the update at the bottom of the page, HEPAP voted to accept the report.


This article appeared in symmetry on Nov. 6, 2013.

Scientists planning the next decade in US particle physics consider what we can learn from fundamental particles called neutrinos.

Scientists planning the next decade in US particle physics consider what we can learn from fundamental particles called neutrinos.

We live in a galaxy permeated with tiny particles called neutrinos. Trillions of them stream through each of us each second. They are everywhere, but much remains a mystery about these particles, which could be key to understanding our universe.

During the first weekend of November, a couple of hundred scientists gathered at Fermilab to discuss ways to unravel the mystery of neutrinos.

The meeting was part of the process of planning the next decade of particle physics research for the United States. A group of 25 scientists on the Particle Physics Project Prioritization Panel, or P5, is studying an abundance of research opportunities in particle physics. In spring they will make recommendations about which of these opportunities should take priority in the United States.

In their first town-hall meeting, the group dedicated a full day to discussing neutrino research.

“Neutrinos have already revealed many properties of the universe, some of them unexpected,” says Antonio Masiero, the vice president of Italy’s National Institute of Nuclear Physics, who provided an international perspective at the meeting. “They still keep secrets which could reveal aspects which are new and answer questions which are still open.”

Neutrinos might help scientists understand what caused the imbalance between matter and antimatter that allowed our universe to form. They could give insight into why particles seem naturally to be organized into three generations. They could help reveal undiscovered principles of nature.

“The neutrino is still a mysterious particle,” says Fermilab physicist Vaia Papadimitriou, pictured above giving a presentation at the meeting. “When I was a graduate student, we didn’t even know neutrinos had masses.”

The next generations of neutrino experiments could reveal other surprises. For example, says Northwestern physicist Andre de Gouvea, neutrinos could turn out to be identical to antineutrinos. They could give scientists clues to the existence of undiscovered types of neutrinos, such as massive ones theorists think might have had a great influence early in the formation of the universe. Neutrinos could turn out to be the only fundamental particles that gain their mass from a source other than the just-discovered Higgs field.

Scientists have proposed a number of experiments to learn more about the properties and behaviors of neutrinos. Those answers could lead to even deeper insights.

P5 will hold at least two more town-hall meetings to discuss additional opportunities in particle physics—including dark matter and dark energy, the Higgs boson, new hidden dimensions of space and time, and the imbalance between matter and antimatter.

Kathryn Jepsen


If you had walked into the CMS control room (P5) today 8th of March of 2010, you would have seen an almost only-women crew at the controls.  It was my last day on-call for the CMS high level trigger system, so I had to attend the daily meeting at CMS P5.  It was fun to see an overwhelming number of women.

I haven’t been paying much attention, and I don’t know the statistics, but I have the feeling that there’s usually a good mix of women and man in the control room. As a matter of fact, this past week (when I was on-call and I had to go to P5 every day) both run field managers were women and I guess they continue for this week.

The fun part of today was that they managed to schedule women for 32 out of the 34 shift positions required to run the CMS experiment; or at least that’s what I was told.  I am sure those two other spots were not filled in with women because the women that can cover them are very busy.  Like my boss, for example, who were supposed to be here for this day but couldn’t make it because she is rather busy with some other CMS responsibilities in the US.

Now, I am curious if they could manage to do the inverse though, i.e., have mostly man scheduled for shifts.  That would be an interesting exercise; it won’t be easy for sure, as many women in CMS have essential expertise in many areas.

All in all it was a good day,  it definitely felt like a special day, and that’s always a lot of fun.  It smelled very nice too!

Hope all women had a good day !!

Edgar Carrera (Boston University)


I happened to be on-call for the CMS High Level Trigger (HLT) system during the week all LHC experiments saw their first collisions, so here I describe (after having some time to breath) my experience.

All the hardware subsystems in the CMS experiment have two kind of people taking care of operations.  The ones in the front-line are the so-called “shifters”, operators who sit in front of several computer screens in the control room and whose job is to monitor closely the performance of each component, and take rapid action in case something goes wrong.  Each shift is usually of 8 hours and there is always someone doing this; the operations are 24/7.  The other kind are the “experts”, who are on-call 24/7 in case there is a major problem or a more involved task that needs to be done.  For this first week, however, shifters and experts were intensively working together in the control room making sure everything works as planned.

For software subsystems, like the HLT, there are also shifters, but who usually sit somewhere else (like in the remote control room across the Atlantic, at the LPC at Fermilab) and who take the usual 8 hours shifts.  The CMS control room at P5 is always connected via video with the other remote stations, including Fermilab, Desy, CMS Meyrin centre, etc.

The experts are of two kinds, the primary and the secondary.  The team of people in charge of expert support rotate between these two states.  The primary is usually the main expert who carries a cell phone all the time in case there is an “emergency” call from the control room.  The secondary is there for backup, in case the primary needs support or if the primary is unreachable for any circumstances. The week before the collisions week I was secondary, and the primary responsibility was transferred to me the day of first collisions, so it was a very exciting (also quite stressful) moment.

The HLT system is a crucial part of the system.  After the first level of triggering (called L1), the HLT is responsible for deciding what goes into tape and what not.  For the expected first collisions, of course, there was no room for mistake.   We had to be able to record these events and make sure we don’t miss them for circumstances like timing synch of the beam with our trigger (L1), timing of the subdetectors, or any other eventuality.  The beam conditions for these first pilot runs are not as stable (and the detectors are not fully calibrated, we need collision events for that!), so we needed to make sure we considered all scenarios.  On Saturday and Sunday, before Monday 23 of November (the day of first collisions), everyone was working very enthusiastically to prepare for this.  I remember sitting down with the Run Coordinator (the person in charge of all operations), together with expert people related to the data acquisition, in order to define a strategy and adapt quickly to the expected (and not so expected) beam conditions.  We worked intensively to make sure the small modifications that needed to be done were carefully executed.

By Monday morning we were ready and very confident that if the delivered beams were to collide at the CMS detector, we were going to be able to see them and record them.  Unfortunately, on Monday afternoon (when most experiments saw their first collisions), CMS did not see any collision candidate;  everything seemed to be consistent with beam gas, or at most something colliding outside the detector.  Worrisomeness and stress could be briefly noticed  in the faces at the  control room.  But there was no time for that, for many it was the culmination of years of work, and for all of us the beginning of and exciting program, so we went back to work to confirm our explanations of what happened.  I could feel the adrenaline flowing in small but appreciable quantities;  I imagine this chemical flooded many physicists’ bodies that day.

Soon, however, we (CMS+LHC) found out that the beams were  not optimized for collisions at P5 during the afternoon, so we tried again in the evening: the LHC circulated two beams again, now optimized for CMS, and it was marvelous.  The displays showed beautiful events.  There were applauses and champagne!! The machine works !!!!

Edgar Carrera (Boston University)

Candidate Collision Event at CMS

Candidate Collision Event at CMS



It looks like we recorded a very good collision candidate event!! Enjoy!!

Edgar Carrera (Boston University)