This may be the final post I write while I am still in Grade 10. In just 5 days school will be over and the long-awaited Summer 2009 will begin. A lot will happen before the week is out though and I could almost drool from desire when I imagine what awaits in the very near future- Tyler coming on Wednesday night, Summer beginning on Friday afternoon, sleep, no stress, happiness, and most of all, freedom. Enter exams: the final barrier standing in the way of my amazing Summer-to-be. The dreadful procedures begin tomorrow morning and continue until Wednesday. Luckily I start off with English tomorrow, which shouldn’t be too stressful. I’ll then have an hour and a half free to do God-knows-what, followed by physics theory. I think I’m ready. I hope I am. Regardless, I can do nothing about it at this point. Tuesday should be basic. I have Spanish and Modern World History back-to back and then get to go home right after. This will give me a lot of time to study for my final exams; you guessed it- Algebra!

The killer of my soul, the fear of all fears, and the devil’s advocate in my life, Algebra will be the very last exam I have. It will be the last time I have to think as a 10th Grader. It will be the exam that will be the final kick in the butt. I would like to believe that I will rip the exam to shreds (not literally) and get an A, but at this point I am still only semi-prepared. It would really be satisfying to get, for the first time, straight A’s on my exams. You know, just so that I can say, “You know what 10th Grade? You really screwed me over. You were so full of it and had me on my knees, but in the end I beat you across the board! I whooped your sorry little–” …and so on and so on.

At the same time though, the end of 10th Grade means two very sad things. Two very important and special people in my life will be leaving me. Robin and Ms. Chesler will be moving to Winnipeg and Uganda respectively. The reality still hasn’t hit me yet that Friday may be the last time that I ever see the woman who introduced me to photography, helped me form many of my opinions, led me to love English, and without whom, this blog would not even exist. Ms. Chesler, I’ll definitely miss you, and if the friends and I still have lunch in your classroom next year it still won’t ever be your room. Thank you so much for everything! Robin on the other hand I’ll see at least twice over the weekend before she leaves on Monday morning, and I know for sure I will see her even after she leaves, at some point in the far, or even not-so-far future. It doesn’t change the fact though that she, like Tyler and Lanora before her, will be missed on a daily basis and will constantly bee on my mind. As much as I’ll miss her though, it still doesn’t change the fact that I won’t be marrying her when I turn forty. Sorry Robin, but I doubt you’ll need me in that regard anyway.

So as I go into battle tomorrow, for the final time this year I know that the odds are on my side, the chance of victory is very high; however, as will all battles, I will not emerge without a loss. In advance though, I think it is safe for me to declare VICTORY!

At the LHC, top quark production cross section is 10 times larger than Tevatron. At Tevatron pair production cross section is 67 pb while at LHC the cross section is 860 pb. So it is fair to say that top quark decay background is dominant in higgs searches at LHC.

Top quarks always decay to W boson and b quark. So the decay channel is depending on W boson decay. W boson decay to lepton and neutrino with 1/9. Since there are three kind of leptons, the rate of decaying to lepton is going to be 3/9. However tau decays eventually to electron or muon which are soft enough to be removed by applying transverse momentum requirement in the analysis. Experimentally total rate of decaying to lepton will be 2/9. The decay to hadron is 6/9.

Now think about 3 cases. Single lepton plus jets, dileptons and multi-jet.

1. Single lepton plus jets : one W decays leptonically and the other W decays hadronically. Then the rate is 2 x 2/9 x 6/9 = 29.6% of all top quark pair production. 2 is needed because there are two cases.

2. Dileptons : each W decays leptonically. 2/9 x 2/9 = 4.9%. It provides clean samples but there are two neutrinos which makes it hard to reconstruct top mass.

3. Multi-jet : The lagest sample of top quark pair production is 6 jets decay from fully hadronic decay. The branching ratio is 6/9 x 6/9 = 44.4%. However these events suffer from a very large background from multi-jet events.

I am posting it not to forget the branching ratio.

In March 2009, D0 and CDF reported electroweak single top decay discovery at Tevatron. The cross section of single top quark 0.14 pb at Tevatron and 68 pb at LHC. It will be also interesting to see the single top result from LHC.

I suppose nearly everyone has seen the famous image to the right of physicist Albert Einstein (1879-1955) sticking out his tongue.  

As this CNN story explains, photographer Arthur Sasse took it in 1951.  Einstein later had nine copies made, and presented one to broadcast journalist Howard K. Smith.

The photo was taken following the celebration of Einstein’s 72nd birthday.  Some think that Einstein’s gesture was an obscure political commentary on McCarthyism and the Communist witch hunts of that era.  

Last Friday, a New Hampshire auction house sold Smith’s copy to a New York autograph specialist named David Waxman.  Waxman’s winning bid of $74,324 makes this the highest sum ever paid for an Einstein photograph.

Greensboro Public Library of course has lots of books on Einstein and his theory of relativity.  Try some of these recent titles:  Einstein’s Mistakes:  The Human Failings of Genius by Hans C. Ohanian; Einstein and Oppenheimer:  The Meaning of Genius by Silvan S. Schweber; Albert Einstein:  A Biography by Milton Meltzer (juvenile); Einstein:  His Life and Universe by Walter Isaacson; A Stubbornly Persistent Illusion:  The Essential Scientific Writings of Albert Einstein edited, with commentary, by Stephen Hawking; Einstein:  A Biography by Jürgen Neffe; A World Without Time:  The Forgotten Legacy of Gödel and Einstein by Palle Yourgrau; Albert Einstein by Aaron Frisch (juvenile); Anticipations of Einstein in the General Theory of Relativity by Christopher Jon Bjerknes; The dark Hole War:  My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics by Leonard Susskind; Reinventing Gravity:  A Physicist Goes Beyond Einstein by John W. Moffat; My Einstein:  Essays by Twenty-four of the World’s Leading Thinkers on the Man, His Work, and His Legacy, edited by John Brockman; Empire of the Stars:  Obsession, Friendship, and Betrayal in the Quest for dark Holes by Arthur I. Miller; and Big Bang:  The Origin of the Universe by Simon Singh.

Sans Everything depends not only on its writers, but also its readers. Given the huge difference between daily site visits and replies to our posts it is clear that the vast majority of visitors to the site are content to read quietly, which is perfectly fine with us. We are also delighted, however, to have some regular readers who themselves have become a part of the blog through their regular responses, and in no case is this more true than with David Sachs.  His interests are as varied as our posts and then some, and he adds immeasureably to our ongoing conversation.

What Sans Everything readers may not know is that David has put together a highly original and very funny podcast entitled Tennis Vagabond, based on a novel he wrote called The Life on Court of Bacon O’Rourke (you can subscribe to the podcast for free). As David explained to me, “Tennis Vagabond follows the young tennis legend Bacon O’Rourke who travels the open road with whiskey in his flask and a racquet on his back, serving and volleying and drinking and toking his way across the land. This comic epic is, in short,  Jack Kerouac with a tennis racquet, and some serious bad guys. The story covers tennis and evil, sex and death, drugs and physics theory, and the dangers in commodifying that which we love. The bad guys in hot pursuit of Bacon and his underground tennis caravan include the mythical Tennis Illuminati (secret masters of the Game), and a down-and-out coach with a taste for detective novels, Zen quips, and funk music. God and the Devil make cameos as tournament umpires.” It also has a physics theory blog, a tennis blog and some memorable video extras (trust me: the strip tennis match is sure to hold the attention of people who otherwise don’t care for tennis).

Tennis Vagabond’s mix of lowbrow and highbrow will appeal to many Sans Everything visitors, and it is also timely in its central message: “a parable of consumerism, commodification, and the progression of open-ended capitalism at a time when those things are being questioned.” But why tennis in particular? David’s answer: “I’m not too sure, but it worked. As Tom Robbins says about hitchhiking in Even Cowgirls Get the Blues, the Truth is there in anything, if you push it far enough (’when it has been pushed far enough it contains everything else’).”

Congratulations, David, and we look forward to hearing of O’Rourke’s continuing adventures!

Next to the kitchen table, my back yard (or front yard) is my favorite science laboratory.  It has the added bonus of being easy to clean up.  For this fun, messy experiment, a hose and a few paper towels did the trick. 

My dad, who is a physicist, told me about this great demonstration that teaches kids a little bit about motion and force while letting them do something that they are rarely, if ever, allowed to do- throw eggs!  All you need is a sheet, some clothespins or string, raw eggs, and some paper.  You could use newspaper or easel paper.  It is just to make cleaning up easier.  I also used a portable table turned on its side as a wall, but you could just use a wall and have your child hose it off when you are finished.

Hang the sheet up from a tree, if you have one.  If you don’t have a tree, you could hang it from anything else, or have two tall children or adults hold it.  Then have two children hold the bottom of the sheet up, or tie it to chairs  so it makes a J shape when you view it from the side.  The idea is to keep the eggs from hitting the ground and breaking. 

Have your child throw a raw egg at the sheet as hard as they can.  It won’t break because the sheet slows the egg down.  The law of motion says that the faster you change speed, the greater the force.  When you change the speed of the egg slowly, like the sheet does, it lessens the force of the egg stopping and the egg remains intact.

Now, put some paper on a wall (or table like we did.)  Have your child throw the egg at the wall.  They will see what happens when something stops fast.  Once again, the law of motion rules.  When you change the speed of the egg quickly, it stops with a lot of force.  SPLAT.  My kids loved this part.  I had to stop them from using all my eggs. 

Tell them that this is one reason they put airbags in cars.  If a car is moving and hits something, causing it to stop very quickly, the airbag act like the sheet, slowing the person in the car down and greatly reducing the amount of force they might hit the dashboard with. 

Have your child record their results in their science notebook, if they want to.  They can write or draw what they did, write the word force and record how many eggs they threw and which ones broke. 

Finally, make sure they wash their hands when they’re done playing and cleaning up.  Remind them that raw eggs can have a bacteria called Salmonella living in them and on them. 

Have fun!

Last week, as part of the CSIRO Scientists in Schools program, I was lucky enough to go on a tour of the Australian Synchrotron.

“Wow!” I hear you say, “That is amazing..but..Mrs Parrington, what is a Synchrotron and what does it do?”

Well, in very simple terms, a Synchrotron is a machine that speeds up really small particles called electrons until they are going nearly as fast as the speed of light. This light is then used by scientists to do all sorts of experiments including medical research, forensic science and minerals exploration (amongst lots of other things!)  It is an amazing machine.

For some more information, have a look at the Australian Synchrotron website here.

The URL for their homepage is: http://www.synchrotron.org.au/content.asp?Document_ID=1

The JET fusion reactor looks more like the lair of a Bond villain than an extraordinary British experiment that might save the world.
www.dailymail.co.uk

Quem nunca ouviu falar do excelente livro Gödel, Escher, Bach: An Eternal Golden Braid (ver também Gödel, Escher, Bach; By Douglas R. Hofstadter)?

Pois bem, o MIT OCW tem um curso inteiro baseado no livro, MIT OCW: GEB. E os vídeos podem ser encontrados aqui, GEB: Video Lectures.

Diversão garantida!

1. Check epsilon correction to D4 PV function

2. Implement E4(mu,nu,ro,si) reduction in Maple

3. Implement F reduction in Maple

4. Summarize one stage PV reduction for each PV function (B,C,D,E)

5. Implement numerical evaluation of tensor/scalar integral, compare with the one using FF

I’ve been thinking a lot about my personal value, here on earth – I can’t help but think there is some greater plan for each of us, and mine – I believe – I may have had under my nose all this time. Everyone has heard about string theory, quantum physics theory, folding time and space, wormholes, the speed of light etc etc.

Due to my natural fascination with physics theory in general, I’ve decided to take it upon myself to research further in what some would clasify the ‘esoteric’ physics theory spectrum where not too many Physicists agree on ideas / concepts. To some these theories or plans to prove / disprove them are too outlandish and hold no ground in Science, I believe there is merit in continueing the epic journey to discover whether these concepts do indeed exist or can be implimented in todays world. The more we try to discover the concepts of folding time / space, the more we push to create our own tear in time – the more of the little things will be discovered which are just as important to us in todays time (cures, productivity, new technologies).

If anyone has some good books to recommend on String theory, wormholes, timetravel etc. please let me know via a comment. If you’d like to contact me, you can view my information about me page, my gtalk information is there (along with email address).

Take care