We study the single-spin (left-right) asymmetry in single-inclusive pion production in hadronic scattering. This asymmetry is power-suppressed in the transverse momentum of the produced pion and can be analyzed in terms of twist-three parton correlation functions in the proton. We present new calculations of the corresponding partonic hard-scattering functions that include the so-called ''nonderivative'' contributions not previously considered in the literature. We find a remarkably simple structure of the results. We also present a brief phenomenological study of the spin asymmetry, taking into account data from fixed-target scattering and also the latest information available from Relativistic Heavy Ion Collider (RHIC). We make additional predictions that may be tested experimentally at RHIC.

In neutral cold quark matter that is sufficiently dense that the strange quark mass Ms is unimportant, all nine quarks (three colors; three flavors) pair in a color-flavor locked (CFL) pattern, and all fermionic quasiparticles have a gap. We argue that as a function of decreasing quark chemical potential µ or increasing Ms, there is a quantum phase transition from the CFL phase to a new "gapless CFL phase" in which only seven quasiparticles have a gap. The transition occurs where M 2 s /µ ≈ 2∆, with ∆ the gap parameter. Gapless CFL, like CFL, leaves unbroken a linear combinationQ of electric and color charges, but it is aQ-conductor with a nonzero electron density. These electrons and the gapless quark quasiparticles make the low energy effective theory of the gapless CFL phase and, consequently, its astrophysical properties qualitatively different from that of the CFL phase, even though its U (1) symmetries are the same. Both gapless quasiparticles have quadratic dispersion relations at the quantum critical point. For values of M 2 s /µ above the quantum critical point, one branch has conventional linear dispersion relations while the other branch remains quadratic, up to tiny corrections. PACS numbers:We know a lot about the properties of cold quark matter at sufficiently high baryon density from first principles. Quarks near their Fermi surfaces pair, forming a color superconductor [1]. In this letter we study how the favored pairing pattern at zero temperature depends on the strange quark mass M s , or equivalently on the quark chemical potential µ, using the pairing ansatz [2]Here ψ α a is a quark of color α = (r, g, b) and flavor a = (u, d, s); the condensate is a Lorentz scalar, antisymmetric in Dirac indices, antisymmetric in color (the channel with the strongest attraction between quarks), and consequently antisymmetric in flavor. The gap parameters ∆ 1 , ∆ 2 and ∆ 3 describe down-strange, up-strange and up-down Cooper pairs, respectively.To find which phases occur in realistic quark matter, one must take into account the strange quark mass and equilibration under the weak interaction, and impose neutrality under the color and electromagnetic gauge symmetries. The arguments that favor (1) are unaffected by these considerations, but there is no reason for the gap parameters to be equal once M s = 0. Previous work [3,4,5,6] compared the color-flavor-locked (CFL) phase (favored in the limit M s → 0 or µ → ∞), and the two-flavor (2SC) phase (favored in the limit M s → ∞). In this paper we show that in fact a transition between these phases does not occur. Above a critical M 2 s /µ, the CFL phase gives way to a new "gapless CFL phase", not to the 2SC phase. The relevant phases areTo impose color neutrality, it is sufficient to consider the U (1) 3 × U (1) 8 subgroup of the color gauge group generated by the Cartan subalgebra T 3 = diag(3 ) in color space [4]. We introduce chemical (color-electrostatic) potentials µ 3 and µ 8 coupled to the color charges T 3 and T 8 , and an electrostatic potential µ e couple...

We study the effect of WIMP annihilation on the temperature of a neutron star. We shall argue that the released energy due to WIMP annihilation inside the neutron stars might affect the temperature of stars older than 10 10 6 years, flattening out the temperature at 10 4 K for a typical neutron star.

We investigate dark matter candidates emerging in recently proposed technicolor theories. We determine the relic density of the lightest, neutral, stable technibaryon having imposed weak thermal equilibrium conditions and overall electric neutrality of the Universe. In addition we consider sphaleron processes that violate baryon, lepton and technibaryon number. Our analysis is performed in the case of a first order electroweak phase transition as well as a second order one. We argue that, in both cases, the new technibaryon contributes to the dark matter in the Universe.Finally we examine the problem of the constraints on these types of dark matter components from earth based experiments. * Electronic address: gudnason@nbi.dk † Electronic address: kouvaris@nbi.dk ‡ Electronic address: sannino@nbi.dk

We argue that observations of old neutron stars can impose constraints on dark matter candidates even with very small elastic or inelastic cross section, and self-annihilation cross section. We find that old neutron stars close to the galactic center or in globular clusters can maintain a surface temperature that could in principle be detected. Due to their compactness, neutron stars can accrete WIMPs efficiently even if the WIMP-to-nucleon cross section obeys the current limits from direct dark matter searches, and therefore they could constrain a wide range of dark matter candidates. * Electronic address: ckouvari@ulb.ac.be † Electronic address: Petr.Tiniakov@ulb.ac.be

We argue that current neutron star observations exclude asymmetric bosonic non-interacting dark matter in the range from 2 keV to 16 GeV, including the 5-15 GeV range favored by DAMA and CoGeNT. If bosonic WIMPs are composite of fermions, the same limits apply provided the compositeness scale is higher than ∼ 10 12 GeV (for WIMP mass ∼ 1 GeV). In case of repulsive self-interactions, we exclude large range of WIMP masses and interaction cross sections which complements the constraints imposed by observations of the Bullet Cluster. Apart from direct searches, constraints on WIMPs can be set by observations of compact objects such as white dwarfs and neutron stars [4][5][6][7][8][9][10][11][12]. These constraints can be grouped in two types. The first type targets WIMPs that can annihilate inside the star producing heat that can change the thermal evolution of the star [5]. WIMPs of this type can arise in supersymmetric extensions of the SM (see [13] and references therein), or in Technicolor models [14]. Constraints of the second type target asymmetric DM models. In these models the annihilation of DM in the present-day Universe is impossible because only particles, and no anti-particles (hence the term "asymmetric") remain [15][16][17][18][19]. An additional bonus in these models is that the asymmetry of WIMPs might be linked through sphalerons with the baryon asymmetry [16,18], which can explain the today's ratio Ω DM /Ω B ∼ 5 provided the WIMP has a mass around 5 GeV. Note that this value is not far from the one suggested by DAMA and CoGeNT. In view of this coincidence, the models with WIMP masses in the GeV range have become quite popular.Since in the asymmetric DM models WIMPs cannot annihilate, if a large number of them is accreted during the lifetime of a neutron star, they may collapse forming a small black hole inside the star that eventually destroy the latter. Therefore the existence of old neutron stars can impose constraints on the properties of asymmetric WIMPs. In fact, in the case of fermionic asymmet-

We put constraints on asymmetric dark matter candidates with spin-dependent interactions based on the simple existence of white dwarfs and neutron stars in globular clusters. For a wide range of the parameters (WIMP mass and WIMP-nucleon cross section), WIMPs can be trapped in progenitors in large numbers and once the original star collapses to a white dwarf or a neutron star, these WIMPs might self-gravitate and eventually collapse forming a mini-black hole that eventually destroys the star. We impose constraints competitive to direct dark matter search experiments, for WIMPs with masses down to the TeV scale. * kouvaris@cp3.sdu.dk † Petr.Tiniakov@ulb.ac.be arXiv:1012.2039v1 [astro-ph.HE] 9 Dec 2010Observations of clusters of galaxies, rotations curves of individual galaxies, cosmic microwave background anisotropies, and many other methods suggest the existence of dark matter. A possible realization of dark matter might be in the form of Weakly Interacting Massive Particles (WIMPs). A huge effort is being undertaken by experimentalists to directly detect WIMPs in underground or space experiments, as well as by theorists to incorporate them into viable theories beyond the Standard Model. The situation experimentally is still not clear, as the majority of the experiments have not detected WIMPs so far. Direct search experiments with Earth based detectors like CDMS [1] and Xenon [2] have imposed constraints on the WIMP-nuclei cross sections, assuming the local dark matter density around the Earth as inferred from the cosmological and other data (see e.g. Ref. [3] for the determination of the amount of dark matter from the WMAP data). On the other hand, DAMA experiment [4] claims dark matter detection with parameters that contradict other experiments if taken at face value. Given the still unclear picture regarding the nature of dark matter, it is of crucial importance to constrain as much as possible the WIMP candidates, including their mass and interactions. Several such candidates exist in the market depending on what theory beyond the Standard Model one chooses, ranging from supersymmetry [5, 6] and hidden sectors [7, 8], to Technicolor [9-15]. The WIMPs can be classified according to their properties, i.e. if they are produced thermally, if they are asymmetric [9, 16, 17], if they have spin-dependent or spin-independent cross section with the nuclei, if their collisions with the nuclei are elastic or inelastic [18-22], and/or whether they are self-interacting [23-26].Apart from direct searches, constraints on the properties of the WIMPs might arise from astrophysical observations as for example in [27]. Concentration of the WIMPs within stars can affect, under certain circumstances, the evolution of the latter, and/or products of WIMP annihilation within the stars could be directly or indirectly detected. The capture of WIMPs in the Sun and the Earth [28][29][30] has been used to predict a possible signature for an indirect detection of dark matter based on neutrino production due to WIMP co-annihilation [31,32...

Minimal walking technicolor models can provide a nontrivial solution for cosmological dark matter, if the lightest technibaryon is doubly charged. Technibaryon asymmetry generated in the early Universe is related to baryon asymmetry, and it is possible to create an excess of techniparticles with charge ( ÿ 2). These excessive techniparticles are all captured by 4 He, creating techni-O-helium tOHe atoms, as soon as 4 He is formed in big bang nucleosynthesis. The interaction of techni-O-helium with nuclei opens new paths to the creation of heavy nuclei in big bang nucleosynthesis. Because of the large mass of technibaryons, the tOHe ''atomic'' gas decouples from the baryonic matter and plays the role of dark matter in large scale structure formation, while structures in small scales are suppressed. Nuclear interactions with matter slow down cosmic techni-O-helium in the Earth below the threshold of underground dark matter detectors, thus escaping severe cryogenic dark matter search constraints. On the other hand, these nuclear interactions are not sufficiently strong to exclude this form of strongly interactive massive particles by constraints from the XQC experiment. Experimental tests of this hypothesis are possible in the search for tOHe in balloon-borne experiments (or on the ground) and for its charged techniparticle constituents in cosmic rays and accelerators. The tOHe atoms can cause cold nuclear transformations in matter and might form anomalous isotopes, offering possible ways to exclude (or prove?) their existence.