![]() For this purpose, low-energy experiments exploiting lasers, microwave cavities, strong electromagnetic fields, torsion balances, and so forth seem to be superior. Unlike for WIMPs, teraelectronvolt colliders are not the best means to search for WISPs. The latter may also contain light moduli fields and light gravitinos as WISP candidates. These particles are frequently encountered in string embeddings of the Standard Model. Additional WISP candidates are massless or light extra, hidden U(1) gauge bosons as well as light chiral fermions charged under this hidden U(1). Prominent candidates for such particles are axions and axion-like particles (ALPs), and they often arise as Nambu-Goldstone bosons associated with the breakdown of global symmetries. Many of the above-mentioned extensions of the Standard Model predict not only WIMPs, but also WISPs (very weakly interacting subelectronvolt particles). Moreover, the vacuum energy density of the universe, as inferred from cosmological observations, points to the subelectronvolt range, ρ Λ ∼ meV 4. Indeed, atmospheric, reactor, and solar neutrino data strongly support the hypothesis that neutrinos have masses in the subelectronvolt range. However, there is also evidence of fundamental physics at the subelectronvolt scale. Some of these particles, such as neutralinos, are natural candidates for the constituents of cold dark matter (CDM) in the form of so-called weakly interacting massive particles (WIMPs). Indeed, most proposals to embed the Standard Model of particle physics into a more general, unified framework-notably those based on string theory or its low-energy incarnations, supergravity and supersymmetry-predict new heavy ( m≳100 GeV) particles that may be searched for at teraelectronvolt colliders. There is much circumstantial evidence that the teraelectronvolt-scale physics exploited at the LHC will provide decisive insights into fundamental questions such as the origin of particle masses, the nature of dark matter in the universe, and the unification of all forces, including gravity. Thankfully, this book – an edited volume of 40 biographies written by world experts – fills that vacuum somewhat.We are entering an exciting time in particle physics: The Large Hadron Collider (LHC) is setting a new benchmark at the high-energy frontier and, through the collision of multiteraelectronvolt protons, is probing the structure of matter and space-time at an unprecedented level. Unfortunately, getting to know them more deeply was surprisingly difficult: there are disappointingly few biographies about female physicists and their letters and recollections often went unrecorded. They simply leapt out at me from the page: in acknowledgements, in photographs, sometimes even as lead authors on scientific papers. For me, it was a delight to go beyond Marie Curie to find many female physicists. In part, this was because they never went on to become well known, and their contributions – including those by Harriet Brooks, Marietta Blau and Bibha Chowdury – were only recognised many years later. In my research, I found that women – often unpaid or working in the role of assistants and students – were frequently left out in other books. Those who play a lesser role in the story are often simply left out, and these omissions can be compounded with biases and stereotypes. As a result, stories of scientific discovery are often told as if by a few lone geniuses, or (to put it bluntly) great white men. Yet we writers dare not involve every single character in a team of fifty or we know we’ll soon lead our readers – and editors – to despair. Science is not an individual pursuit, but a team one. ![]() Out of the Shadows: Contributions of Twentieth-Century Women to Physics *Later, thanks to quantum mechanics, it became clear that even nothingness – vacuum – wasn’t quite as it seemed. In his wonderful, deeply researched book, Cathcart tells the in-depth story of the race to build the first particle accelerator and in particular the work of the indefatigable John Cockcroft and the young Irishman Ernest Walton, along with the larger-than-life Ernest Rutherford and his modest but ingenious colleague James Chadwick. Getting at the atomic nucleus and understanding its nature required far more complex experiments than ever before, leading to a dramatic race from around 1927 to 1932 to build the first particle accelerator. In between, physicists realised in the early 20th Century, is nothing* at all.ĭespite this, the nucleus contains around 99.97 per cent of the atomic mass, so is crucially important to our understanding of the atom. If we expanded the atom to the size of a cathedral, we would find that while the electrons lie out at the cathedral walls, the nucleus at its heart would be so tiny it would be no bigger than a fly. The atom is astonishing in many ways, but particularly in its dimensions. ![]()
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