Meyer Lemon Martinis: This One's For You, Mom.

My mom is a martini woman. Not the spine-straightening vodka and vermouth type; that's my Uncle Frank's specialty. Jeweled, slightly sweet and tingly refreshing drinks like cosmopolitans are more her style. When I come home to visit we usually spend an evening sitting at the kitchen counter, sipping cocktails. It's always wonderfully relaxing. Here is a drink I think she'll like.

One of my best friends from college, Jasmin, lives across the bay in San Francisco. We try to get together a couple of times a month for dinner and drinks. This weekend I hosted and was trying to decide what to make for dessert. Our apartment building has a Meyer lemon tree in the backyard (pictured) which is currently producing copious amounts of lemons and consequently everything I am cooking lately features lemons. I decided that dessert should be lemon-centric but nothing I saw on the internet or in my cookbooks looked either appealing or easy enough to be worth making. Then an idea occurred to me: who needs dessert when you can make cocktails?! A visit to Google and a few clicks later I had a recipe for Meyer lemon martinis, which I've reproduced below. Mmmmm, Mmmmm, they were delicious!

Meyer Lemon Martinis
2 oz Vodka
.75 oz meyer lemon juice
.5 oz lemon-infused simple syrup (instructions below, increase to .75 oz if using normal lemons)
* a shot glass is 1.5 oz

Mix, shake, and pour, that's all there is too it! To serve I ran a squeezed lemon half around the rim of our flared-mouth wine glasses and then coated the rims with sugar.

Lemon-infused Simple Syrup

2 parts water
1 part sugar
lemon zest to taste (I put one lemon's worth of zest in 1.5 cups of water)

Put the water, sugar and lemon zest in a pot, stir until the sugar is dissolved and heat until just boiling. Take off the heat and let cool, strain and store in the fridge.

You know it's gone too far when...

You find the following in your inbox:

In order to optimize the number and organization of ATLAS meetings, we have put in place a "Meeting Optimization committee"

I kid you not. Meetings to organize meetings. I am a physicist, right? Just checking....

Update: In conversation with one of my colleagues we realized that a committee on meetings was the only logical course of action for the experiment to try to reign in the rapidly multiplying meeting agenda. And then we realized how sad it was that we found the committee to be natural. We are in too deep; we have been assimilated!

Lift Off

The space shuttle Atlantis lifted off today on a mission to fix the Hubble Space Telescope. Hubble has been mostly blind for the past couple of years, loosing one of the cameras in January 2007 and another in 2008. The astronauts are trying to fix both cameras and put in a new instrument, new gyroscopes and remove some old cameras at the same time. Hopefully they get it all done!

Cosmic Variance has a nice report on the launch. It's amazing to watch the shuttle lift off and know that people are traveling into orbit. I saw Star Trek this weekend (it was good!) and while the everything in the movie is pure fantasy, watching a shuttle launch plants a little irrational thought that maybe someday we'll achieve a tiny piece of what the screenwriters imagined.

Et Voilà, Baguette!

Friday evening I stumbled home and flung myself on the couch after seven straight days of talks. Yep, seven. APS had begun the previous Saturday at 8:30 am and lasted through Tuesday. I got on a plane back to Berkeley Tuesday afternoon, missing the last half day of APS talks, and Wednesday morning I was back at LBL for a 7:30am meeting. That meeting was followed by the start of a workshop which lasted until Friday evening. When I flung myself down on the couch my brain was so saturated I vowed to not think about physics for the entire weekend. My plan for the weekend included sleeping, bike riding, cooking, and attempting to bake a decent baguette. I am happy to report that I had a wonderful weekend accomplishing all four of the above activities and almost succeeded in not doing any physics!


This post is to detail the baguette making, which was just as satisfying, if not more so, than the bagel making. The baguettes are made pain à l’ancienne style, detailed in Peter Reinhart’s book, which involves letting the fridge do most of the fermentation work. The result was a wonderfully crusty, sweet and nutty baguette which I couldn’t quite believe came out of my oven. I was supremely happy the rest of the day. It’s funny how flour, yeast, water and salt can do that to you.

Baguettes à l’Ancienne from Peter Reinhart’s The Bread Baker’s Apprentice

6 cups unbleached bread flour (27oz)
2 1/4 teaspoons salt (fine sea salt)
1 3/4 teaspoons instant yeast (increase by 25% if using active dry)
2 1/4 -3 cups ice-cold water (needs to be as cold as possible)
Semolina or cornmeal for dusting
*you will need an oven-safe, heavy duty skillet and a spray bottle of water for the baking stage

Step 1: Mixing

Stand Mixer Instructions: Combine the flour, salt, yeast and water in the bowl of the electric mixer with the paddle attachment and mix for 2 minutes on low speed. Switch to the dough hook and mix for 5 to 6 minutes on medium speed. The dough should be sticky on the bottom of the bowl, but it should release from the sides of the bowl. If not, sprinkle in a small amount of flour until this occurs (or dribble in water if the dough seems too stiff and clears the bottom as well as the sides of the bowl).

Hand Mixing: Standmixing is much preferred because it minimizes contact with the dough so it doesn’t heat up as much. However, I was using my stand mixer and didn’t realize that the dough had climbed up the dough hook and got a bunch of grease in it from the place where the hook attaches to the machine. I decided to start over and hand mix it with the following process. Combine the flour, salt and yeast in a large, wide mouthed bowl. Add the water and mix (by hand or spoon) until combined. Then, dip your hand in cold water and knead the dough inside the bowl by holding the bowl with one arm and using the other hand as a dough hook, folding and pressing the dough against the sides of the bowl. Do this for about 10 minutes. I think my dough got a bit too warm and wasn't quite sticky enough, even though I added more than the 2 1/4 cups of water. Next time I will add closer to 3 cups.

Step 2: Refrigeration
Lightly oil a large bowl and immediately transfer the dough with a spatula or bowl scraper dipped in water into the bowl. Mist the top of the dough with spray oil and cover the bowl with plastic wrap. Immediately place the bowl in the refrigerator and chill overnight, to retard fermentation.


Step 3: Final Fermentation
The next day, check the dough to see if it has risen in the refrigerator. It will probably be partially risen but not doubled in size (the amount of rise will depend on how cold the refrigerator is and how often the door was opened). Leave the bowl of dough out at room temperature for about 2 to 3 hours (or longer if necessary) to allow the dough to wake up, lose its chill, and continue fermenting.

Step 4: Shaping
Prepare the oven for hearth baking by putting a baking stone at the bottom and a heavy duty skillet on a rack near the top to function as a steam pan. Preheat the oven to 500 F, or 550 F if your oven goes this high. Boil ~4 cups of water and keep covered near by. Cover the back of two big sheet pans with baking parchment and dust with semolina flour or cornmeal. If you don’t have a baking stone you will just cook the bread on the back of the sheet pans.
When the dough has doubled from its original prerefrigerated size, liberally sprinkle the counter with bread flour (about 1/2 cup). Gently transfer the dough to the floured counter with a plastic dough scraper or spatula that has been dipped in cold water, dipping your hands as well to keep the dough from sticking to you. Avoid punching down the dough as you transfer it, to expel as little as possible of the carbon-dioxide gas that has built up in the dough during fermentation.
If the dough is very wet, sprinkle more flour over the top as well as under it. Dry your hands thoroughly and then dip them in flour. Roll the dough gently in the sprinkled flour to coat it thoroughly, simultaneously stretching it into an oblong about 8 inches long and 6 inches wide. If it is too sticky to handle, continue sprinkling flour over it.

Dip a metal pastry scraper into cool water to keep it from sticking to the dough, and cut the dough in half widthwise with the pastry scraper by pressing it down through the dough until it severs it, then dipping it again in the water and repeating this action until you have cut down the full length of the dough. (Do not use this blade as a saw; use it as a pincer, pinching the dough cleanly with each cut.) Let the dough relax for 5 minutes.

Take one of the dough pieces and repeat the cutting action, but this time cut lengthwise into 3 equal-sized pieces. Then do the same with the remaining half.
Flour your hands and carefully lift one of the dough strips and transfer it to an inverted parchment-lined pan, gently pulling it to the length of the pan or to the length of your baking stone. If it springs back, let it rest for 5 minutes and then gently pull it out again. Place 3 strips on the pan, and then prepare another pan and repeat with the remaining strips.
Score the dough strips as for traditional baguettes, slashing the tops with 3 diagonal cuts. Because the dough is sticky, you may have to dip the razor blade, serrated knife or scissors in water between each cut. You may also omit the cuts if the dough isn't cooperating.

Step 5: Baking
Take one pan to the preheated oven and carefully slide the dough, parchment and all, onto the baking stone (depending on the direction of the stone, you may choose to slide the dough and parchment off the side of the sheet pan instead of off the end); or bake directly on the sheet pan. I recommend wearing long sleeves and using oven mits or gloves and hot pads.
Make sure the pieces aren't touching (you can reach in and straighten the parchment or the dough strips, if need be). Pour 1 cup of the hot water you set aside into the steam pan and close the door.

After 30 seconds, spray the oven walls with water from the spray bottle and close the door. Repeat twice more at 30-second intervals. After the final spray, reduce the oven setting to 475 F and continue baking.

Meanwhile, dust the other pan of strips with flour, mist with spray oil, and cover with a towel or plastic wrap. If you don't plan to bake these strips within 1 hour, refrigerate the pan and bake later or the next day.

The bread should begin to turn golden brown within 8 or 9 minutes. If the loaves are baking unevenly at this point, rotate them 180 degrees. Continue baking 10 to 15 minutes more, or until the bread is a rich golden brown and the internal temperature registers at least 205 F.
Transfer the hot breads to a cooling rack. They should feel very light, almost airy, and will cool in about 20 minutes.

While these are cooling, you can bake the remaining loaves, remembering to remove the parchment from the oven and turn the oven up to 500 F or higher before baking the second round.

A Standby: Spicy Leek and Tomato Sauce

I'd like to share a standby recipe that I use whenever I have leeks on hand and not much time to make dinner. I've adapted it from a 2007 Bon Appétit recipe which I found on Epicurious. What I'm going to suggest below is enough for 5 or 6 people, or dinner for 2 and lunch for a couple of days after. I used canned tomatoes, but when it's tomato season I use fresh ones. Also, all of the ingredient quantities are very approximate.


Linguine with Spicy Leek and Tomato Sauce

• 1/4- 1/2 cups extra-virgin olive oil
• 4 chopped garlic cloves, or 3 green garlic bulbs(?), white parts only, split lengthwise, sliced crosswise
  
• 1-1 1/2 teaspoon dried crushed red pepper
• 1 1/2 teaspoon fennel seeds
• 3-4 medium leeks (white and pale green parts only), split lengthwise, sliced crosswise
• 2 large cans diced tomatoes, 2/3 of the juice removed
  
• 1 cup dry white wine
• 2 tablespoons white wine vinegar * can be left out if you don't have any
• 1 box of linguine or pasta of your choice
• 2 cups of Parmesan

In a very large skillet or sauce pan heat on medium enough oil to cover the bottom, which should be approximately 1/4-1/3 a cup. Add the garlic or green garlic, red pepper and fennel seeds and stir until the garlic is fragrant and softening, a couple of minutes. Add the leeks and saute until soft, about 8-10 minutes. You can cover the pan if you want, but remember to stir it frequently. You want the leeks to be soft because they won't soften much more in the following steps. Add the tomatoes, removing 2/3 or the liquid from the cans before adding. Stir to mix then add the wine and the vinegar. Cover and cook until the tomatoes breakdown, about 10 minutes.

Meanwhile, cook pasta in large pot of boiling salted water until tender but still firm to bite. Drain, reserving a cup or so of the pasta cooking liquid.

Back to the large sauce pan which is still on medium heat: Add the pasta and a drizzling of oil and toss. Add ~1 cup cheese and toss until mixed, add some of the cooking liquid if the sauce seems dry. Season with salt and pepper. Serve with a sprinkling of extra cheese and a drizzle of nice olive oil to finish. The olive oil drizzle is key, it makes the flavors pop!

APS: Fermi Results

I am on my way back from the 2009 American Physical Society (APS)’s April meeting (in May). It was an exciting, well run conference and I thoroughly enjoyed myself.

The big news of the conference was the high energy electron+positron cosmic ray spectrum that the Fermi telescope released during the first talk of the meeting. As I mentioned in my previous post, cosmic rays are particles which are constantly bombarding the earth’s atmosphere. They consist of a mixture of protons, electrons, positrons (positively charged electrons), photons and a mix of heavier elements. They originate in a variety of sources ranging from astrophysical accelerators such as pulsars, supernovae remnants and active galactic nuclei which can accelerate particles to high energies to the sun. It is also believed that the cosmic ray flux could contain the decay products of dark matter annihilation. Dark matter comprises 25% of the known energy density in the universe, 5% goes to the normal matter that you, I and the stars are made of, and 70% percent goes to something so mysterious that we call it dark energy. Sounds spooky, right? There are many theories of what the dark matter could be made of but all we know for sure is that it interacts extremely rarely, giving it the property of ‘darkness’.

Newly released Fermi results (red) of the electron and positron flux compared with the conventional diffuse model of cosmic ray flux (blue). For more information Physics has a technical article about it.

Eluding detection, dark matter has been a persistent thorn in the side of particle physicists and astrophysicists alike since Fritz Zwicky proposed it in 1933 after observing the rotational velocity of stars in galaxies. Stars orbit the center of their galaxy at a speed that is dependent upon the mass inside their orbits. We can measure the speed of the stars using the doppler effect and we can determine how much mass we think is there by measuring the amount of light we see. However, once you compare the mass in the galaxy and the velocity of the stars you find that you need many more times the mass that you see to generate the speed of the stars. Dark matter was proposed to fill this gap and has been verified in diverse and numerous observations.

There are a number of experiments investigating the flux of cosmic rays to try to find evidence of dark matter annihilation. In the past 6 months or so there have been several exciting yet unconfirmed measurements published. The ATIC experiment found an excess of electrons+positrons at high energy and, in a different energy range, the Pamela experiment found an excess of positrons relative to the number of positrons+electrons. Fermi, a state of the art satellite telescope designed to look at gamma rays and other cosmic rays, was supposed to clarify the situation. They released the results of electron+positron flux on Saturday morning and rather than clearing up the picture, it is now fuzzier. They do not see the same excess that ATIC sees, yet their data does not agree with the standard simulations of galactic cosmic rays. Looking at their data you could see an excess if you wanted to but if you don’t you can convince yourself its not there as is often the case with ambiguous results.

My concern with all of these experiments is that the signal is very small compared to the flux of protons, their main background, and their background rejection efficiency decreases in the region where the excess grows. A mis-measurement of the efficiencies, resolutions or the errors could make a big change in the results. I’m not yet convinced that these results are evidence for dark matter, and I think there are many who would agree with me.

It's important to note that there is a simple astrophysical solution which could explain the data. People have proposed that there is one or more nearby pulsars that are creating the excess that we haven’t found yet. However pulsars are mundane to particle physicists so that explanation was mostly ignored, especially by the theorists. It was amusing to see how quickly they showed plots comparing their favorite models to the new data.

A composite image of the pulsar containing Crab Nebula showing the X-ray (blue), and optical (red) images superimposed. The size of the X-ray image is smaller because the higher energy X-ray emitting electrons radiate away their energy more quickly than the lower energy optically emitting electrons as they move.

The experiments are in the process of further investigating their data. Fermi should release their high energy gamma ray data soon and Pamela will release their positron+electron flux measurement which can be directly compared to the Fermi data. If either of these signals confirm what we’ve seen already the case for dark matter will become more convincing. Until that time, however, I like the suggestion of a commenter in one of the sessions: “Members of each experiment should be locked in a room without weapons...and not let out until they figure this mess out”.

Hi From Denver

I’m in Denver for the 2009 American Physical Society (APS) April Meeting. You might be saying, Wait! It’s not April anymore! And you would be correct. This meeting, which consists of particle physicists, astrophysicists and nuclear physicists, is traditionally in April. There is another yearly APS meeting, the March Meeting, which is for everything else. To distinguish the two they call them by the months in which they’ve traditionally been held.

This meeting consists of 4 days of 10 minute talks mostly by graduate students and post-doc, interspersed with longer plenary style talks from important invited speakers. I’m giving a talk tomorrow morning in the Instrumentation in High Energy Physics session. I’ll be talking about ATLAS’s tracking performance with cosmic rays. Even though the LHC is not running, the ATLAS detector is, and luckily Mother Nature provides us something to look at. (Actually, it's not running this Spring in order to do some maintenance.) The earth’s atmosphere is constantly being bombarded by particles from space which we call cosmic rays. Hundreds are passing through you right now. Modern particle physics was founded on the study of these particles, which can reach much higher energies than we can create in accelerators. ATLAS is 100 meters under the ground, so we see only one type of cosmic ray, the muon, which is created when a primary cosmic rays hits the Earth's atmosphere and decays. Particle physicists love muons. They are heavy and only interact via the electromagnetic and weak forces so they pass through most material relatively unhindered. Last fall ATLAS used these particles to start understanding how the detector works. It is such a massive machine that it takes an immense amount of calibration work before you can start doing physics. The cosmic rays give us a perfect opportunity to do that calibration in a simple environment since we usually see only one of them at a time. In a proton collision like what the LHC will deliver we will see hundreds! I’ve been looking at the performance of our Inner Detector, a set of 3 tracking detectors which work together to measure a particle’s trajectory and momentum. The conclusion of the study is that it is performing very well!

The picture is an artist's rendition of the showers of particles produced when ultra high energy cosmic rays interact in the atmosphere.

There is word that some exciting results will be released tomorrow. I’ll probably write about that and I’ll be writing posts through out the rest of conference as interesting topics come up!