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Tuning the level September 24, 2008

Posted by dorigo in personal, physics.

As much as I try to write physics in this blog in a way that is understandable for most readers (or at least for those willing to sit down and try to understand), I frequently end up with posts that are too technical, too detailed, and of too little interest to outsiders. My usual formula for a physics post is to introduce the matter for everybody, possibly lingering around very down-to-earth explanations, before delving in the technicalities; however, that is sometimes easier said than done.

Lately I have been receiving erratic input from independent sources about the level of my posts being a bit too high. Today, for instance, a reader who studied Physics for two years before leaving Academia said he understood just about 40% of my recent post on the Vista-Sleuth algorithm. That is too bad, since this site has as main reason for its existence the attempt to do some outreach on experimental particle physics. So I really want to make an effort in the direction of simplifying the posts, but of course I cannot restrain myself to non-technical discussions in all cases. So I need to implement some visual tool to enable readers to decide quickly whether a post is for insiders only or for everybody. I am thinking at different styles of text, or text color. Another way could be to give a rating with tiny Einstein icons next to the title – but such luxuries are not available to standard users of wordpress stuff. Any suggestions ?

I would also like to use this occasion to invite all readers who happen to read through my physics posts (those describing physics analyses) to rate them in the comments thread, pointing out at the places where more clarity could have improved the text. Am I asking for too much ? Probably I am, but I know there are a few among you that are willing to help.



1. John Green - September 24, 2008

Hi Tomaso,
Here is a question for you, and I would really love to have an answer for it.
If I am a new graduate student who wants to go for experimental particle physics at CDF (or D0) what would you advise me to learn? If you are my adviser, what do you expect me to know? Or start learning?

Thank You for your blog and for all the post that made me love this field.

2. dorigo - September 24, 2008

Dear John,

thank you for your interest in particle physics and my blog.

Now, the proper background that allows one to get a PhD program in CDF or D0 is kind of standard, and it of course includes quantum mechanics, field theory, and particle physics courses.

However, I think you know what the regular HEP curriculum includes in major universities, and you are probably asking for what I personally think are the most important ingredients to become skilled with data analysis in an experiment like CDF or D0.

I think one ingredient which is very important is the study of weak interactions, starting from the first experiments, the discovery of the nature (V-A) of the charged current, and the various symmetry principles and their violations. These things are contained in most particle courses, but recently there has been the tendency to give them less importance, due to the availability of a lot of more recent material to discuss. I think instead that the experimental and phenomenological physics of the fifties and the sixties is very important if studied properly, because one learns things that are relevant for today’s experiments but one also sees the direct connection between hints and experimental verifications, something of which we have had fewer and fewer examples as time went by.

Besides weak interactions and a good understanding of electroweak unification, I think it is very useful to study hadron collider phenomenology, something which is not available in many books, but rather in school writeups. QCD in proton-antiproton collisions is very interesting, but complicated if taken from a theoretical standpoint. One needs a basic understanding of some important things, such as color coherence, fragmentation, parton distribution functions and their effect in hard and soft interactions.

Another important ingredient is a good statistics course, one centered on real examples of data analysis. There was a course at CERN a few months ago, there are writeups somewhere. This is very high-level stuff however. I am unaware of lower-level courses, introductory but still aimed at framing the mind of experimentalists rather than listing theorems.

And of course, one needs to become capable with C++ programming. It is not a strict requirement -I know people in HEP who do not know what a pointer is, and I am not too far from that- but very useful to know the basics.

Hope that helps,

3. John Green - September 24, 2008


Thank you so much for this thorough answer, I am impressed. I thought programming skills is an essential part in your work. I have had some chat with some experimentalist and they said it is an important part.
So, as a starter at any of these experiments, I should know C++. A friend of mine at one of these experiments said that Fermilab softwares and some graphing codes are essential.

So, all in all, one does not have to be a genius at programming with C++ but has to have some mastery over physics materials.

Thank you so much Tomaso for your reply.


4. chimpanzee - September 25, 2008


You need a multi-pronged solution, different posts directed to different audiences:

“The right Tool, for the Right Problem..I keep tellin’ you!”
— Scotty, Star Trek

I’m a Elec Eng PhD (no background in Particle Theory, though I did take a graduate level Physics course in Group Theory..which I don’t even recall being 25 yrs ago), & your technical posts way are over-my-head! There are some research-area specific knowledge, that I’m missing (Ignorance).

It would help if you had a tutorial section on the right side-bar “Particle Physics for Dummies”. A section for HS student, Undergrads in Physics, Physics grad students, researchers. Basic tutorials in Particle Theory, Experimental Particle Physics, statistical analysis, flowchart of progress in Particle Physics: both theoretical & Experimental. This reminds me of my discussion with John Doyle/Caltech (Nonlinear Dynamics & Control Theory), when I asked him

Q: “Where is a central source for information on your field”.
A: “It’s SCATTERED. Amongst journal papers, books, papers in Proceedings/Conferences”.

This is the story for Science & Engineering: there is no *standardized* reference for each field’s research flow-chart. Say, like the Standard Handbook for Chemistry.

There is a solution to the above “central source”..a tell-all book. This is what Carver Mead/Caltech & Lynn Conway/XEROX PARC did: publish a VLSI book. It described their revolutionary technique (as a vehicle for acceptance by their peers), LC got invited to MIT to teach this course (out of the book), & the rest..as they say is History.

Relevant excerpts from above URL:
– – the term foundry later became very controversial – – – it really bugged lots of people, who didn’t like it’s apparent dethroning of fab as the end-all, be-all of chipmaking – – (note: the term is now in everyday use in the semiconductor industry) – – Carver always had a way of bringing notice to himself ,and to our work, by confronting traditionalists with what seemed to be rather outrageous claims, and with inventive, but slightly offensive, new terminology! – – Carver was always memorable! – – –

The idea of writing “the book”
– – – in a meeting at PARC with Carver, Doug, Jim and few other folks in the late spring of ’77, it was late in the day; we were tired, and kidding around and winding things down – – I had finally hit on a specific idea, and AI just said it out loud: “Let’s write a book on the new methods!” – – – “a book that looks like the kind of textbook you might see after such methods had been used for many years and were all proven out in practice – – full of design examples, etc.” – – to my surprise, Carver instantly said “Yeah!”, very, very loudly – – and that was it: we set off to do “The Book” – – thus another of “Lynn’s wild projects” was about to take off – – –
– – during the summer of ’77 and on into early ’78 Lynn, Carver, Doug, Jim, Bob Sproull, Dick Lyon, and Carlo Sequin all teamed up to help brainstorm about, create and test this book – – this was an incredibly talented set of folks, and we really infected each other with our mutual excitement about the work – – – a series of versions were written and tried in preliminary courses – – the first three chapters in a course taught by Carlo at U.C. Berkeley – – then the first 5 chapters (including the OM-2 design examples) in a course by Bob Sproull at CMU – – – at this point we decided to change the title from Introduction to LSI Systems to Introduction to VLSI Systems – – just about that time I’d seen “VLSI” as an acronym a couple of times in Electronics Magazine, and thought it would add the right additional flair to the title – – we still called my PARC group the LSI System Area for a while, but we’d change that a bit later too – –

[ pulling in research contributions from fellow peers ]

– – our secret weapons in rapidly writing and evolving the textbook were the Alto computers, laser printers, and Arpanet access at PARC

[ 30 yrs later, we have sophisticated laptops/desktops, with Blogging/Web/desktop content creation (text, photo, video) solutions to add to the old fashioned email/word-processors. So, I think Tommaso has a “big project” ahead of him. I’ve been in private communication to him, about how Mobile Technology can aid the whole Blogging solution: for Research & Outreach applications ]

– – – I did most of the writing and editing of the emerging text on my Alto – – receiving input from Carver at Caltech re the OM-2 – – and exchanging drafts, doing editing, and collaborating with an ever increasing number of contacts at other places, using e-mail and file transfers via the Arpanet – – this infrastructure: the Alto personal computers, ethernet and laser printers at PARC, Arpanet, e-mail, etc., way back in ’77, was very similar in effectiveness to the modern PC’s – – and gave us an amazing ability to rapidly create, distribute for checking, refine and self-publish drafts of the emerging text – –

The crash effort to evolve and propagate the new methods
– – – and thus began a crazy, intense period – – – “this was it” – – the time to really crank up, and make hay – – it was now or never – – – and most everything else in my life ceased, except work – – –
– – – for the next several years, I worked six or seven days of the week, often for 12 to 16 hours a day – – at my Alto – – writing, e-mailing, FTPing files, – – – getting up early, drinking coffee all day – – going home late – – drinking some wine to finally crash at night – – then back at it the next day – – – day after day, month after month – – – (by 1980, this phase had almost ruined my health) – – writing “the book” – – – and coordinating activities in an ever-enlarging “VLSI community” out in the network – – –
– – in the spring of ’78, Bert suggested an exciting, but very challenging possibility – – he was on the visiting committee of the EECS department at MIT – – he’d talked about the Mead-Conway work with folks there – – he offered me a “sabbatical”, a chance to teach at MIT that next fall and introduce the new methods there – –

A really great story of how the VLSI Revolution took place. It took an interesting 2-person team (Caltech & Xerox/PARC) to work jointly towards a goal. A great example of how Concept -> Execution. The entire “Retrospectives” should be read as a “leadership by example”. It has relevance to ANY researcher out there who has a dream.

“Nothing happens, if not first a dream”
— Carl Sandberg

I think Tommaso could be on the forefront of a revolution: Outreach/Education book for HEP. Given the recent LHC setback, maybe this is an opportunity for him to try this Content/Distribution point. I am a specialist in iTunes video-podcast, so a video version of this Outreach/Education on iTunes could be lucrative. Kinda like Lisa Randall’s “Warped Passages” popular book.

A friend of mine (Cal State LB astronomy instructor) told me Greg Binford (UC Irvine Physics prof, famous Sci-Fi writer) is really wealthy because of popular sales of his Sci-Fi book (5 million copies). This model could be a way out of the “intellectually rich, but monetarily poor” modus-operanda of profs.

5. tripitaka - September 25, 2008

I am perfectly happy for the contect to be way above my level of understanding since I don’t need to understand every aspect to get the general thrust, and higher level posts allow for more substantial technical debate between commenters (which I usually don’t understand but which give insight as to where the real action in HEP might lie). I’m too lazy to be seeking genuine education in HEP anyway…
In short, the authentic glimpses into the pointy end of HEP at this site are just gold, really thats the beauty of the whole blogging phenomenon where experts from every imaginable field inexplicably decide to spend their free time sharing their passions with the masses. Thankyou for this site

6. Alessandro - September 25, 2008

dorigo says:
“So I need to implement some visual tool to enable readers to decide quickly whether a post is for insiders only or for everybody.”

“Another way could be to give a rating with tiny Einstein icons next to the title – but such luxuries are not available to standard users of wordpress stuff. Any suggestions ?”

Keep it simple, put the complexity level in the post title:
[*] – This post is for everybody
[**] – This post is for insiders
[***] – This post is for very experts


7. Francisco Barradas - September 25, 2008

Dear Tommaso,

I agree with most of which chimpanzee, tripitaka and alessandro say; you can write posts aimed at different audiences (but perhaps not too different though, or many readers could feel either discouraged or bored).

Many of your posts (take, for instance, the last two devoted to physics, about omega b minus and the search for new physics at fermilab) are just what I need and can’t find easily outside your blog; not just popular physics, but enough technical detail so as to get a (good) glimpse of what high energy physicists really do.
I am a high-school physics teacher with a physics degree and, to do my job properly I feel that I need to hear about statistics, kinematic fits, backgrounds, signatures, simulations… and I know that I’m not the only one; I have found many colleagues so inclined at CERN’s excellent HST programme for high school teachers. Of course, there are be times when I may not understand properly everything you say, but I do not think that is too important.

Have you heard of a book by Coughlan, Dodd and Gripaios called “The Ideas of Particle Physics: An Introduction for Scientists, 3rd ed.”? It is aimed at, in the authors’ words, “graduates in the physical sciences and other numerate subjects”. I wish we had a similar book but with more emphasis on experimental methods (“from raw data to physics results”could be the title) and I’m certain that you could do it!

Thank you and keep going!

8. dorigo - September 25, 2008

Hello Francisco,

yes, I will keep going – it is input such as yours that does it.

As for a book, yes, it would be nice… I would certainly like to write something like that, and maybe I will, but it takes effort to find the time!


9. dorigo - September 25, 2008

Chimpanzee, Alessandro, yes, I think the idea of having different offers is good. I would still like to provide both an introduction for everybody and technical input in the same post. I will think about the idea of a classification scheme – I had indeed thought of asterisks, but they look a bit artificial to me.

Maybe I can do something else. I like the idea of color-coding the technical parts…. Also italics could work.

Ciao Tripitaka,

thank you so much for your encouragement, you made me blush, so I’ll repay you… A kiss!


10. goffredo - September 25, 2008

Was it Einstein that said something like this:
“Make things as simple as possible, but not simpler”

Yes I think it would be nice that a book be written that told in reasonable detail some nice recent HEP experimental cases; from theory, to apparatus design, construction, calibration, analysis… .

Tommaso has the energy and talent to do it.

11. Markk - September 25, 2008

Well, I have a BS in physics and graduate degree elsewhere. Some of the your articles of course have things beyond me, or I suspect beyond anybody currently working in the area, but I think the level is good. It is better to stretch comprehension than not. The areas and issues you put up are not found anywhere else at the level you do.

Of course the chess articles do blow my mind 🙂 (What is check again? … well I’m not quite that ignorant.)

12. Marco - September 26, 2008

I enjoy your posts. My education was Civil Engineering and so my college level physics stopped in my sophomore year. I don’t pretend to understand everything(not even close), but I am attracted to your writings. I gleam information and you don’t have to write to my level. I like the idea you are true to your scholarship and since I am not a student or researcher I don’t need to understand everything.. Just every once in a while explain the ramifications of research.and the possibilities they present. Of course whenever you throw in anything about that great Italian cuisine my mouth waters. You are doing great! No need to change for me.

13. tulpoeid - September 26, 2008

I was actually about to suggest something more or less relevant one of these days; many of your “more technical” articles are quite useful for (us) grad students, since standard textbooks of what somebody actually DOES in order to have his bloody work done are non-existent in experimental elementary particle physics. It still belongs to those arts that are passed down on a person-to-person basis, as it seems.
So my suggestion is an assortment-post with links to all of your previous posts that fall in the category I described. It’s de useful, it’d be great, it could even be cited in phd’s.
Ok I didn’t exactly answer your question, but at least my point of view on whether the level of your posts is good or bad should be clear…

14. tulpoeid - September 26, 2008

I’m sorry for the italics, bad syntax. It was supposed to end at “work done”. :/

15. dorigo - September 26, 2008

Hi Jeff,

well, thank you so much. I can resist anything but adulation, as O.Wilde would say. I admit it, I would like to do something like that one day… Maybe I will, maybe I will.

Hi Markk,
actually that is exactly what I too think: stretching one’s comprehension is useful, in general. Thanks for the input.

Ciao Marco,
well, I do not much cooking myself, although when I am away for a while I do. I appreciate your understanding for my inability to manage to be for everybody, sometimes.

Hi Tulpoeid, I can either leave it there as is or correct it and remove your last comment… I guess it is just easier to leave everything there.
In any case: collecting a pointer to the most relevant posts is a good thing, but it is *very* time consuming. I am actually thinking that I could open a poll of what could be the things to link, asking readers to mine my blog… Tiresome business! There are 1300 posts here, maybe 800 with a “physics” tag…

Cheers all,

16. snark - September 27, 2008

I know of no other source that even attempts to describe the material you cover. Some posts are very difficult, some more basic.
Personally, I have no desire to have them rated before hand, I enjoy working through both, even if I cannot fully grasp the details. And the occaisional divergences are great. Chess, bridge, Italian politics, and of course, Lisa Randall.. I enjoyed modelling – was it a poisson muon decay and uniform background? – detector problem. Vastly simplified perhaps, but a pleasant way of understanding the problem. You are asking for a more detailed, and deserve a longer, perhaps more serious response, but i wouldn’t want you to change anuything. The work you have put in is deeply appreciated.

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