The Newtonian Legacy

The Newtonian Legacy by N J Evans, www.hep.phys.soton.ac.uk/~evans/NL.

There are many free novels available online, but this is probably the only one by a particle theorist. In this e-book, Nick Evans explains modern particle physics for a lay-readership as the background to a murder mystery. WPC Thatcher, a police officer who had previously studied physics, is leading the investigation into the death of a researcher at a physics institute. Her enquiring mind leads her also to ask questions about the Standard Model and beyond.

Reviews on Evans’ web page show that his project is succeeding. Meanwhile, for readers of CERN Courier, the author has found a lost chapter – "Higgsless Dreams". Read on!

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WPC Thatcher lay in the darkness, a disconnected consciousness in limbo. Stray worries competed for spare processing time as she tried to sleep, unaware of the room around her or the bed she lay upon. That is until her partner, sprawled next to her, gave out a loud isolated snore breaking the illusion.

Sometimes Mike’s grunts would irritate her, but tonight they seemed tolerable or even endearing. Perhaps this was the result of pheromonal warfare between the sexes, she reflected – they had made love earlier.

She was awake after a run to the kitchen to get a warmed bottle of milk for her daughter who had balled for it at 3 a.m. She’d have managed five hours sleep by then – not enough, but sufficient to make a return to oblivion near impossible. She wasn’t sure if she’d been awake hours or just minutes since then. Actually she was in that murky state of consciousness where she wasn’t entirely sure she wasn’t asleep.

The state of their bank balance was clammering for attention. It was near the end of the month and she had meant to check online. She’d worked really hard to ensure a £200 a month pay rise in the previous spring, but it didn’t seem to make any difference to the bottom line a week before pay day. She could look in the morning, so why was she worrying about it now?

Think of something else then. Kissing Mike, his weight on top of her. Drowsy pleasure, the first hints of warmth between her thighs… well that wasn’t going to get her to sleep!

Try again – work… she was investigating a strange death. A physicist at the local institute, called the Phi, had been found dead in the grounds – it seemed to be connected to a chemical laboratory he was running at his home. Her degree, which had been in physics, although she could barely dredge up anything specific now, made her the best qualified of the police team to talk to the man’s academic colleagues.

The Phi Institute was a centre for the study of theoretical particle physics. The staff seemed to spend their time dreaming up new theories of the most fundamental building blocks of nature – electrons and quarks and so forth, from which all materials are made. They took their ideas and then mathematically calculated the consequences for big experiments that collide particles together at enormous energies. They all seemed to have been waiting for years for an experiment called the Large Hadron Collider to switch on – this machine, in Geneva, Switzerland, will collide protons, creating fireballs with 10 times more energy than ever achieved before. The big hope apparently was to use this energy to create new particles through the famous Einstein E = mc² relation, which means mass is just a form of energy.

Now, she wondered, could she remember the thread of this? The main focus was trying to understand the weak nuclear force – a force involved in radioactive decay. The particles of matter have charge under this force, just as electrons carry electric charge. These charges interact through fields that permeate space, communicating the presence of one charge to another and controlling their attraction or repulsion. There are such fields for the weak force just as for electromagnetism.

Somehow those fields are like particles, she remembered. Ah yes! That’s quantum theory – the energy in the fields turns out to be divided into lumps. If you interact with the field you might get given a lump of energy or two, but never half a lump. Those lumps of energy behave like particles – the lumps of an electric field are called photons (the same things that make up light, since light is an excitation of electric and magnetic fields).

Now the problem with the weak force lumps (the W bosons was it?) was that they were very massive, unlike photons that are massless. E = mc² again tells us they have some intrinsic energy associated with that mass that photons don’t have. So you can’t just simply adapt electromagnetic theory and get the weak force.

Enter the theorists – they all seem to believe in this new particle called the Higgs boson. Their explanation was that all of space, even the vacuum between planets, is filled with vast numbers of these new Higgs particles. The Higgs particles have weak force charge so the W bosons keep interacting with them. It’s like filling space with treacle; the Higgs particles impede the progress of the W bosons. The energy of that interaction is the W boson mass.

The only problem is that they’ve never made a Higgs particle. So, concluded the WPC, pleased with herself, that’s what they’re all looking for.

Is that really the only explanation, she wondered? There must be a theorist who’s dreamt up another possibility, surely? Perhaps not? She should look on the internet – Maybe she could learn something that would put the Phi staff off story!

Maybe she should really go to sleep? She rolled onto her side. She’d bought a sweater on Sunday – that might have pushed them overdrawn… for goodness sake… It’s no good, she concluded, she was going to have to get up and check their bank balance.

Mike didn’t move as she shifted to a sitting position and found her slippers. He had earned "midnight-milk-monster" duties for tomorrow she resolved. She padded out of the room across the landing and down the stairs. The first hints of dawn were creeping through the windows and, combined with the light they left on in the hall below, made her path clear.

She paused in the hall to examine her reflection in the large mirror hung on the wall. Her short blonde hair was crushed and askew and she had big black smudges under her eyes. The long, faded, white T-shirt with teddy bears across the front, which was all she was wearing, seemed overly twee. She’d used to look cute in it, hadn’t she? Was she looking old or just feeling it? Still, who wants to be a cute policewoman? Some instinctive part of her subconscious still whispered against this rational conclusion.

The computer painted her in a blue glow from the desktop background when she moved the mouse. She summoned up a browser and clicked away to their account summary – it was as bad as she’d feared, though not quite overdrawn. Mike had been in town shopping last Wednesday, judging by the wracked-up debits. Funny, she thought, but he’d probably said and she’d forgotten.

Back to bed? Instead she Googled the word "higgsless". There were lots of hits – interesting… she clicked on one at random summoning the abstract of a scientific paper onto the screen. Kaluza Klein… moose… quiver… unitarity… Well, that was pretty unreadable, not to mention bizarre.

Suddenly some part of her brain had caught up with prior events and she found herself frowning. One of those payments from their account had been to Pink Moon – that was a lingerie shop in town. Another had been a chocolate shop. Her heartbeat raced a little and the blood drained from her face. Was Mike cheating on her? She tried to scan back through her life seeking other signs – it was just work and her daughter though. That didn’t seem very reassuring. Don’t panic, you’re being silly – he probably bought them for me, she thought. Not that it was her birthday anytime soon, nor Valentine’s. How about their wedding anniversary? He never remembered that and anyway it was five weeks away. God, she’d been doing so many late nights he could have been anywhere. Maybe she even deserved it then. The word "neglect" came to mind.

Cling to the wedding anniversary idea for a moment – she’d noticed only recently that their every weekend between now and then was booked up with children’s parties, visiting relatives and so forth. And she had made a big fuss about Mike forgetting last year. So she was accusing him of infidelity just because he was more organized than her. She was going to have to find the time to buy him something good now. The panic had ebbed away, well almost.

She clicked on a few more links to distract herself. Finally she got a PowerPoint show that made a little sense. It had been written by some mid-west US professor as part of his research group’s presentation to the Department of Energy for renewed funding. Interestingly, when they needed money these professors appeared to become a lot more comprehensible. She could imagine the panic as they tried desperately to make their talks accessible but not patronizing. Actually, she really could read this one, so the prof. had probably opted for patronizing in his own view!

Apparently the most urgent need for the Higgs was to solve a problem in the theory of scattering two W bosons. Without the Higgs, theory would predict that the probability of two Ws scattering was greater than one (What? If you flip a coin half the time it will come up heads and half the time it will come up tails but it always adds up to one. Oh, that’s the problem!). If you include the Higgs then all is well.

The same job can be achieved by the inclusion of new heavier copies of the W particles, the presentation continued. It only works for a little bit though, if you give the Ws too much energy you get the same problem again. So then you add in yet more W particles to solve the problem again, and so on indefinitely.

None of this removes the need to explain where the W masses come from though. There seemed to be two ideas – firstly you could eventually resort to a Higgs (or many of them) to generate all these W masses. What you gain from the tower of Ws is that the Higgs mass could be much larger than it would be otherwise, so you might not find it at the LHC.

The second possibility was a bit more bizarre. Apparently you could choose to never end the tower of new Ws – every time you go to a higher energy you just keep finding a new W. If this happened it would mean you’d found an extra dimension of space! Weird.

There was a picture of a spatial direction (not up–down, sideways, or forward and back, but a new direction) which was a tiny circle. If you head off in this new direction you end up back where you started (this seemed to be an acceptable thing to happen, to this professor at least). This direction was going to be so short (smaller round than an atom is across) that in everyday life we’re oblivious to it.

Next there were pictures of the weak force field going round this circle. However it wiggled it always had to come back to the same value after going round the circle.

That means only very special weak force field configurations are allowed. Depending on how much they wiggle they have a certain amount of energy – that energy determines the mass of the associated W particles. You could always add an extra wiggle before you get back to the start so that’s why there is an infinite tower of more and more massive Ws.

Well that was kind of interesting. The mid-west professor had lost patience with his attempts at pedagogy at that point though and the following pages were a mass of equations that meant nothing to the WPC.

The slide’s use as a distraction was over and she was still stressing about Pink Moon. If Mike had bought her a present he’d have to have hidden it somewhere in the house. That wasn’t so easy for him because she did the washing and cleaning so she got to poke her nose most places. Modern equality culture required her to mentally qualify this thought with the point that they had tried an equal sharing of all duties but she’d just not been up to the physicality of cutting the hedge and painting over the stairs. They shared the cooking so the kitchen was out. Likewise the car. Well, she thought, that pretty much leaves the tool cupboard in the garage.

She was just left with the moral dilemma then. If she went to look it would be effectively accusing Mike and spying, wouldn’t it? She could just wait and see what happens on their anniversary. She wasn’t going to be able to think about much else in the meantime though.

She rolled the mouse to show her the final page of the physics presentation. Higgsless models were possible in principle but the extra Ws had to be rather heavy to explain why we hadn’t yet found them, and no completely satisfactory theory yet existed. These physicists always seemed to be waiting to find out the answer. She didn’t have their patience.

The WPC switched off the computer screen and walked out into the kitchen. She unlocked and opened the door into the garage. The fluorescent tube buzzed loudly when she switched it on – she hoped Mike was fast asleep. The car was on the drive so it was easy to reach and open the store cupboard. She realized she wasn’t breathing. Please God.

Garden tools hung neatly from hooks on the back wall of the cupboard. Stacked black plastic flower pots covered the shelf top. A large garden waste bag was on the floor, its top neatly turned over to hide its contents. She reached down to open the bag – her hand was shaking. Inside was a carefully placed Pink Moon bag.

The WPC crept back into bed next to her husband, mentally chastising herself. As she lay down Mike rolled over and blearily asked,

"What are you doing? Did you go in the garage?"

"Can’t sleep, just mooching,"

"I thought you’d lost something important."

"Nothing’s that crucial… except you." They curled together and fell asleep.